5.1-7.1GHz Wi-Fi6E COEXISTENCE ACOUSTIC WAVE RESONATOR RF DIPLEXER CIRCUIT

ABSTRACT

An RF diplexer circuit device using modified lattice, lattice, and ladder circuit topologies. The diplexer can include a pair of filter circuits, each with a plurality of series resonator devices and shunt resonator devices. In the ladder topology, the series resonator devices are connected in series while shunt resonator devices are coupled in parallel to the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a plurality of series resonator devices, and a pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. A multiplexing device or inductor device can be configured to select between the signals coming through the first and second filter circuits.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part application of thefollowing commonly owned patent application: U.S. patent applicationSer. No. 17/151,552, filed Jan. 18, 2021. The present application alsoincorporates by reference, for all purposes, the following patentapplications, all commonly owned: U.S. patent application Ser. No.14/298,057, titled “RESONANCE CIRCUIT WITH A SINGLE CRYSTAL CAPACITORDIELECTRIC MATERIAL”, filed Jun. 6, 2014, now U.S. Pat. No. 9,673,384;U.S. patent application Ser. No. 14/298,076, titled “METHOD OFMANUFACTURE FOR SINGLE CRYSTAL CAPACITOR DIELECTRIC FOR A RESONANCECIRCUIT”, filed Jun. 6, 2014, now U.S. Pat. No. 9,537,465; U.S. patentapplication Ser. No. 14/298,100, titled “INTEGRATED CIRCUIT CONFIGUREDWITH TWO OR MORE SINGLE CRYSTAL ACOUSTIC RESONATOR DEVICES”, filed Jun.6, 2014, now U.S. Pat. No. 9,571,061; U.S. patent application Ser. No.14/341,314, titled “WAFER SCALE PACKAGING”, filed Jul. 25, 2014, nowU.S. Pat. No. 9,805,966; U.S. patent application Ser. No. 14/449,001,titled “MOBILE COMMUNICATION DEVICE CONFIGURED WITH A SINGLE CRYSTALPIEZO RESONATOR STRUCTURE”, filed Jul. 31, 2014, now U.S. Pat. No.9,716,581; U.S. patent application Ser. No. 14/469,503, titled “MEMBRANESUBSTRATE STRUCTURE FOR SINGLE CRYSTAL ACOUSTIC RESONATOR DEVICE”, filedAug. 26, 2014, now U.S. Pat. No. 9,917,568; and U.S. patent applicationSer. No. 16/995,598, titled “RF BAW RESONATOR FILTER ARCHITECTURE FOR6.5 GHZ WI-FI 6E COEXISTENCE AND OTHER ULTRA-WIDEBAND APPLICATIONS”,filed Aug. 17, 2020.

BACKGROUND OF THE INVENTION

The present invention relates generally to electronic devices. Moreparticularly, the present invention provides techniques related to amethod of manufacture and a structure for bulk acoustic wave resonatordevices, single crystal bulk acoustic wave resonator devices, singlecrystal filter and resonator devices, and the like. Merely by way ofexample, the invention has been applied to a single crystal resonatordevice for a communication device, mobile device, computing device,among others.

Mobile telecommunication devices have been successfully deployedworld-wide. Over a billion mobile devices, including cell phones andsmartphones, were manufactured in a single year and unit volumecontinues to increase year-over-year. With ramp of 4G/LTE in about 2012,and explosion of mobile data traffic, data rich content is driving thegrowth of the smartphone segment—which is expected to reach 2B per annumwithin the next few years. Coexistence of new and legacy standards andthirst for higher data rate requirements is driving RF complexity insmartphones. Unfortunately, limitations exist with conventional RFtechnology that is problematic, and may lead to drawbacks in the future.

With 4G LTE and 5G growing more popular by the day, wireless datacommunication demands high performance RF filters with frequenciesaround 5 GHz and higher. Bulk acoustic wave resonators (BAWR) usingcrystalline piezoelectric thin films are leading candidates for meetingsuch demands. Current BAWRs using polycrystalline piezoelectric thinfilms are adequate for bulk acoustic wave (BAW) filters operating atfrequencies ranging from 1 to 3 GHz; however, the quality of thepolycrystalline piezoelectric films degrades quickly as the thicknessesdecrease below around 0.5 um, which is required for resonators andfilters operating at frequencies around 5 GHz and above. Singlecrystalline or epitaxial piezoelectric thin films grown on compatiblecrystalline substrates exhibit good crystalline quality and highpiezoelectric performance even down to very thin thicknesses, e.g., 0.4um. Even so, there are challenges to using and transferring singlecrystal piezoelectric thin films in the manufacture of BAWR and BAWfilters.

From the above, it is seen that techniques for improving methods ofmanufacture and structures for acoustic resonator devices are highlydesirable.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, techniques generally related toelectronic devices are provided. More particularly, the presentinvention provides techniques related to a method of manufacture andstructure for bulk acoustic wave resonator devices, single crystalresonator devices, single crystal filter and resonator devices, and thelike. Merely by way of example, the invention has been applied to asingle crystal resonator device for a communication device, mobiledevice, computing device, among others.

In an example, the present invention provides an RF diplexer circuitdevice. The diplexer can include a first filter circuit and a secondfilter circuit coupled to a multiplexer or inductor device. The firstfilter circuit can be configured to receive a first input signal and toproduce a first filtered signal, while the second filter circuitconfigured to receive a second input signal and to produce a secondfiltered signal. Each of these filter circuits includes a plurality ofseries resonators and a plurality of shunt resonators. The multiplexeror inductor device is coupled to the first filter circuit and the secondfilter circuit and can be configured to select between the firstfiltered signal and the second filtered signal.

Each of the resonators can include a substrate member, which has acavity region and an upper surface region contiguous with an opening inthe first cavity region. Each resonator device can include a bottomelectrode within a portion of the cavity region and a piezoelectricmaterial overlying the upper surface region and the bottom electrode.Also, each resonator can include a top electrode overlying thepiezoelectric material and the bottom electrode, as well as aninsulating material overlying the top electrode and configured with athickness to tune the resonator. As used, the terms “top” and “bottom”are not terms in reference to a direction of gravity. Rather, theseterms are used in reference to each other in context of the presentdevice and related circuits. Those of ordinary skill in the art wouldrecognize other modifications, variations, and alternatives.

In an example, the piezoelectric materials can include single crystalmaterials, polycrystalline materials, or combinations thereof and thelike. The piezoelectric materials can also include a substantiallysingle crystal material that exhibits certain polycrystalline qualities,i.e., an essentially single crystal material. In a specific example, thefirst, second, third, and fourth piezoelectric materials are eachessentially a single crystal aluminum nitride (AlN) bearing material oraluminum scandium nitride (AlScN) bearing material, a single crystalgallium nitride (GaN) bearing material or gallium aluminum nitride(GaAlN) bearing material, a magnesium hafnium aluminum nitride (MgHfAlN)material, or the like. In other specific examples, these piezoelectricmaterials each comprise a polycrystalline aluminum nitride (AlN) bearingmaterial or aluminum scandium nitride (AlScN) bearing material, or apolycrystalline gallium nitride (GaN) bearing material or galliumaluminum nitride (GaAlN) bearing material, a magnesium hafnium aluminumnitride (MgHfAlN) material, or the like. In other examples, thepiezoelectric materials can include aluminum gallium nitride(Al_(x)Ga_(1-x)N) material or an aluminum scandium nitride(Al_(x)Sc_(1-x)N) material characterized by a composition of 0≤X<1.0. Asdiscussed previously, the thicknesses of the piezoelectric materials canvary, and in some cases can be greater than 250 nm.

In a specific example, the insulating materials include a siliconnitride bearing material, an oxide bearing material, or combinationsthereof.

In an example, a first circuit response of the first filter can beconfigured between the first input port and the output port andconfigured from the serial configuration and the parallel configurationof the first filter device to achieve a first transmission loss from afirst pass-band. Further, a second circuit response can be configuredbetween the second input port and the output port and configured fromthe serial configuration and the parallel configuration of the secondfilter device to achieve a second transmission loss from a secondpass-band.

In a specific example, the each of the pass-bands is characterized by aband edge on each side of the pass-band and having an amplitudedifference ranging from 10 dB to 60 dB. Each of the pass-bands has apair of band edges; each of which has a transition region from thepass-band to a stop band such that the transition region is no greaterthan 250 MHz. In another example, each of the pass-bands can include apair of band edges and each of these band edges can have a transitionregion from the pass-band to a stop band such that the transition regionranges from 5 MHz to 250 MHz.

In an example, the resonators of the first and second filter devices canbe configured in ladder configuration. In this case, the plurality ofseries resonators is configured in a serial configuration and theplurality of shunt resonators is configured in a parallel configuration.In a specific example, the serial configuration forms a resonanceprofile and an anti-resonance profile. The parallel configuration alsoforms a resonance profile and an anti-resonance profile. These profilesare such that the resonance profile from the serial configuration isoff-set with the anti-resonance profile of the parallel configuration toform the pass-band.

In an example, the resonators of the first and second filter devices canbe configured in a lattice configuration. In this case, the plurality ofseries resonators includes a first plurality configured in a firstserial configuration and a second plurality configured in a secondserial configuration. The plurality of shunt resonators includes aplurality of shunt resonator pairs, each of which are cross-coupledbetween one of the first plurality of series resonators in the firstserial configuration and one of the second plurality of seriesresonators in the second serial configuration. In a specific example,this lattice configuration can include a plurality of baluns orinductors, each of which is coupled between the first and second serialconfigurations and configured between each of the plurality of shuntresonator pairs.

One or more benefits are achieved over pre-existing techniques using theinvention. In particular, the present device can be manufactured in arelatively simple and cost-effective manner while using conventionalmaterials and/or methods according to one of ordinary skill in the art.The present device provides an ultra-small form factor RF resonatorfilter with high rejection, high power rating, and low insertion loss.Such filters or resonators can be implemented in an RF filter device, anRF filter system, or the like. Depending upon the embodiment, one ormore of these benefits may be achieved.

A further understanding of the nature and advantages of the inventionmay be realized by reference to the latter portions of the specificationand attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the present invention, reference ismade to the accompanying drawings. Understanding that these drawings arenot to be considered limitations in the scope of the invention, thepresently described embodiments and the presently understood best modeof the invention are described with additional detail through use of theaccompanying drawings in which:

FIG. 1A is a simplified diagram illustrating an acoustic resonatordevice having topside interconnections according to an example of thepresent invention.

FIG. 1B is a simplified diagram illustrating an acoustic resonatordevice having bottom-side interconnections according to an example ofthe present invention.

FIG. 1C is a simplified diagram illustrating an acoustic resonatordevice having interposer/cap-free structure interconnections accordingto an example of the present invention.

FIG. 1D is a simplified diagram illustrating an acoustic resonatordevice having interposer/cap-free structure interconnections with ashared backside trench according to an example of the present invention.

FIGS. 2 and 3 are simplified diagrams illustrating steps for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention.

FIG. 4A is a simplified diagram illustrating a step for a methodcreating a topside micro-trench according to an example of the presentinvention.

FIGS. 4B and 4C are simplified diagrams illustrating alternative methodsfor conducting the method step of forming a topside micro-trench asdescribed in FIG. 4A.

FIGS. 4D and 4E are simplified diagrams illustrating an alternativemethod for conducting the method step of forming a topside micro-trenchas described in FIG. 4A.

FIGS. 5 to 8 are simplified diagrams illustrating steps for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention.

FIG. 9A is a simplified diagram illustrating a method step for formingbackside trenches according to an example of the present invention.

FIGS. 9B and 9C are simplified diagrams illustrating an alternativemethod for conducting the method step of forming backside trenches, asdescribed in FIG. 9A, and simultaneously singulating a seed substrateaccording to an embodiment of the present invention.

FIG. 10 is a simplified diagram illustrating a method step formingbackside metallization and electrical interconnections between top andbottom sides of a resonator according to an example of the presentinvention.

FIGS. 11A and 11B are simplified diagrams illustrating alternative stepsfor a method of manufacture for an acoustic resonator device accordingto an example of the present invention.

FIGS. 12A to 12E are simplified diagrams illustrating steps for a methodof manufacture for an acoustic resonator device using a blind viainterposer according to an example of the present invention.

FIG. 13 is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention.

FIGS. 14A to 14G are simplified diagrams illustrating method steps for acap wafer process for an acoustic resonator device according to anexample of the present invention.

FIGS. 15A-15E are simplified diagrams illustrating method steps formaking an acoustic resonator device with shared backside trench, whichcan be implemented in both interposer/cap and interposer free versions,according to examples of the present invention.

FIGS. 16A-16C through FIGS. 31A-31C are simplified diagrams illustratingvarious cross-sectional views of a single crystal acoustic resonatordevice and of method steps for a transfer process using a sacrificiallayer for single crystal acoustic resonator devices according to anexample of the present invention.

FIGS. 32A-32C through FIGS. 46A-46C are simplified diagrams illustratingvarious cross-sectional views of a single crystal acoustic resonatordevice and of method steps for a cavity bond transfer process for singlecrystal acoustic resonator devices according to an example of thepresent invention.

FIGS. 47A-47C though FIGS. 59A-59C are simplified diagrams illustratingvarious cross-sectional views of a single crystal acoustic resonatordevice and of method steps for a solidly mounted transfer process forsingle crystal acoustic resonator devices according to an example of thepresent invention.

FIG. 60 is a simplified diagram illustrating filter pass-bandrequirements in a radio frequency spectrum according to an example ofthe present invention.

FIG. 61 is a simplified diagram illustrating an overview of key marketsthat are applications for acoustic wave RF filters according to anexample of the present invention.

FIG. 62 is a simplified diagram illustrating application areas for RFfilters in mobile applications according to examples of the presentinvention.

FIGS. 63A-63C are simplified diagrams illustrating cross-sectional viewsof resonator devices according to various examples of the presentinvention.

FIG. 64A is a simplified circuit diagram of a diplexer device accordingto an example of the present invention.

FIG. 64B is a simplified circuit diagram of a diplexer device accordingto an example of the present invention.

FIGS. 65A-65C are simplified circuit diagrams illustratingrepresentative lattice and ladder configurations for acoustic filterdesigns according to examples of the present invention.

FIGS. 66A-66B are simplified diagrams illustrating packing approachesaccording to various examples of the present invention.

FIGS. 67A-67B are simplified diagrams illustrating packing approachesaccording to an example of the present invention.

FIG. 68 is a simplified circuit diagram illustrating a 3-port BAW RFcircuit according to an example of the present invention.

FIGS. 69A and 69B are simplified tables of filter parameters accordingto examples of the present invention.

FIGS. 70A and 70B are simplified graphs representing passband insertionloss over frequency according to examples of the present invention.

FIGS. 71A and 71B are simplified graphs representing wideband insertionloss over frequency according to examples of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, techniques generally related toelectronic devices are provided. More particularly, the presentinvention provides techniques related to a method of manufacture andstructure for bulk acoustic wave resonator devices, single crystalresonator devices, single crystal filter and resonator devices, and thelike. Merely by way of example, the invention has been applied to asingle crystal resonator device for a communication device, mobiledevice, computing device, among others.

FIG. 1A is a simplified diagram illustrating an acoustic resonatordevice 101 having topside interconnections according to an example ofthe present invention. As shown, device 101 includes a thinned seedsubstrate 112 with an overlying single crystal piezoelectric layer 120,which has a micro-via 129. The micro-via 129 can include a topsidemicro-trench 121, a topside metal plug 146, a backside trench 114, and abackside metal plug 147. Although device 101 is depicted with a singlemicro-via 129, device 101 may have multiple micro-vias. A topside metalelectrode 130 is formed overlying the piezoelectric layer 120. A top capstructure is bonded to the piezoelectric layer 120. This top capstructure includes an interposer substrate 119 with one or morethrough-vias 151 that are connected to one or more top bond pads 143,one or more bond pads 144, and topside metal 145 with topside metal plug146. Solder balls 170 are electrically coupled to the one or more topbond pads 143.

The thinned substrate 112 has the first and second backside trenches113, 114. A backside metal electrode 131 is formed underlying a portionof the thinned seed substrate 112, the first backside trench 113, andthe topside metal electrode 130. The backside metal plug 147 is formedunderlying a portion of the thinned seed substrate 112, the secondbackside trench 114, and the topside metal 145. This backside metal plug147 is electrically coupled to the topside metal plug 146 and thebackside metal electrode 131. A backside cap structure 161 is bonded tothe thinned seed substrate 112, underlying the first and second backsidetrenches 113, 114. Further details relating to the method of manufactureof this device will be discussed starting from FIG. 2.

FIG. 1B is a simplified diagram illustrating an acoustic resonatordevice 102 having backside interconnections according to an example ofthe present invention. As shown, device 101 includes a thinned seedsubstrate 112 with an overlying piezoelectric layer 120, which has amicro-via 129. The micro-via 129 can include a topside micro-trench 121,a topside metal plug 146, a backside trench 114, and a backside metalplug 147. Although device 102 is depicted with a single micro-via 129,device 102 may have multiple micro-vias. A topside metal electrode 130is formed overlying the piezoelectric layer 120. A top cap structure isbonded to the piezoelectric layer 120. This top cap structure 119includes bond pads which are connected to one or more bond pads 144 andtopside metal 145 on piezoelectric layer 120. The topside metal 145includes a topside metal plug 146.

The thinned substrate 112 has the first and second backside trenches113, 114. A backside metal electrode 131 is formed underlying a portionof the thinned seed substrate 112, the first backside trench 113, andthe topside metal electrode 130. A backside metal plug 147 is formedunderlying a portion of the thinned seed substrate 112, the secondbackside trench 114, and the topside metal plug 146. This backside metalplug 147 is electrically coupled to the topside metal plug 146. Abackside cap structure 162 is bonded to the thinned seed substrate 112,underlying the first and second backside trenches. One or more backsidebond pads (171, 172, 173) are formed within one or more portions of thebackside cap structure 162. Solder balls 170 are electrically coupled tothe one or more backside bond pads 171-173. Further details relating tothe method of manufacture of this device will be discussed starting fromFIG. 14A.

FIG. 1C is a simplified diagram illustrating an acoustic resonatordevice having interposer/cap-free structure interconnections accordingto an example of the present invention. As shown, device 103 includes athinned seed substrate 112 with an overlying single crystalpiezoelectric layer 120, which has a micro-via 129. The micro-via 129can include a topside micro-trench 121, a topside metal plug 146, abackside trench 114, and a backside metal plug 147. Although device 103is depicted with a single micro-via 129, device 103 may have multiplemicro-vias. A topside metal electrode 130 is formed overlying thepiezoelectric layer 120. The thinned substrate 112 has the first andsecond backside trenches 113, 114. A backside metal electrode 131 isformed underlying a portion of the thinned seed substrate 112, the firstbackside trench 113, and the topside metal electrode 130. A backsidemetal plug 147 is formed underlying a portion of the thinned seedsubstrate 112, the second backside trench 114, and the topside metal145. This backside metal plug 147 is electrically coupled to the topsidemetal plug 146 and the backside metal electrode 131. Further detailsrelating to the method of manufacture of this device will be discussedstarting from FIG. 2.

FIG. 1D is a simplified diagram illustrating an acoustic resonatordevice having interposer/cap-free structure interconnections with ashared backside trench according to an example of the present invention.As shown, device 104 includes a thinned seed substrate 112 with anoverlying single crystal piezoelectric layer 120, which has a micro-via129. The micro-via 129 can include a topside micro-trench 121, a topsidemetal plug 146, and a backside metal 147. Although device 104 isdepicted with a single micro-via 129, device 104 may have multiplemicro-vias. A topside metal electrode 130 is formed overlying thepiezoelectric layer 120. The thinned substrate 112 has a first backsidetrench 113. A backside metal electrode 131 is formed underlying aportion of the thinned seed substrate 112, the first backside trench113, and the topside metal electrode 130. A backside metal 147 is formedunderlying a portion of the thinned seed substrate 112, the secondbackside trench 114, and the topside metal 145. This backside metal 147is electrically coupled to the topside metal plug 146 and the backsidemetal electrode 131. Further details relating to the method ofmanufacture of this device will be discussed starting from FIG. 2.

FIGS. 2 and 3 are simplified diagrams illustrating steps for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention. This method illustrates the process forfabricating an acoustic resonator device similar to that shown in FIG.1A. FIG. 2 can represent a method step of providing a partiallyprocessed piezoelectric substrate. As shown, device 102 includes a seedsubstrate 110 with a piezoelectric layer 120 formed overlying. In aspecific example, the seed substrate can include silicon, siliconcarbide, aluminum oxide, or single crystal aluminum gallium nitridematerials, or the like. The piezoelectric layer 120 can include apiezoelectric single crystal layer or a thin film piezoelectric singlecrystal layer.

FIG. 3 can represent a method step of forming a top side metallizationor top resonator metal electrode 130. In a specific example, the topsidemetal electrode 130 can include a molybdenum, aluminum, ruthenium, ortitanium material, or the like and combinations thereof. This layer canbe deposited and patterned on top of the piezoelectric layer by alift-off process, a wet etching process, a dry etching process, a metalprinting process, a metal laminating process, or the like. The lift-offprocess can include a sequential process of lithographic patterning,metal deposition, and lift-off steps to produce the topside metal layer.The wet/dry etching processes can includes sequential processes of metaldeposition, lithographic patterning, metal deposition, and metal etchingsteps to produce the topside metal layer. Those of ordinary skill in theart will recognize other variations, modifications, and alternatives.

FIG. 4A is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device 401 according to an exampleof the present invention. This figure can represent a method step offorming one or more topside micro-trenches 121 within a portion of thepiezoelectric layer 120. This topside micro-trench 121 can serve as themain interconnect junction between the top and bottom sides of theacoustic membrane, which will be developed in later method steps. In anexample, the topside micro-trench 121 is extends all the way through thepiezoelectric layer 120 and stops in the seed substrate 110. Thistopside micro-trench 121 can be formed through a dry etching process, alaser drilling process, or the like. FIGS. 4B and 4C describe theseoptions in more detail.

FIGS. 4B and 4C are simplified diagrams illustrating alternative methodsfor conducting the method step as described in FIG. 4A. As shown, FIG.4B represents a method step of using a laser drill, which can quicklyand accurately form the topside micro-trench 121 in the piezoelectriclayer 120. In an example, the laser drill can be used to form nominal 50um holes, or holes between 10 um and 500 um in diameter, through thepiezoelectric layer 120 and stop in the seed substrate 110 below theinterface between layers 120 and 110. A protective layer 122 can beformed overlying the piezoelectric layer 120 and the topside metalelectrode 130. This protective layer 122 can serve to protect the devicefrom laser debris and to provide a mask for the etching of the topsidemicro-via 121. In a specific example, the laser drill can be an 11W highpower diode-pumped UV laser, or the like. This mask 122 can besubsequently removed before proceeding to other steps. The mask may alsobe omitted from the laser drilling process, and air flow can be used toremove laser debris.

FIG. 4C can represent a method step of using a dry etching process toform the topside micro-trench 121 in the piezoelectric layer 120. Asshown, a lithographic masking layer 123 can be forming overlying thepiezoelectric layer 120 and the topside metal electrode 130. The topsidemicro-trench 121 can be formed by exposure to plasma, or the like.

FIGS. 4D and 4E are simplified diagrams illustrating an alternativemethod for conducting the method step as described in FIG. 4A. Thesefigures can represent the method step of manufacturing multiple acousticresonator devices simultaneously. In FIG. 4D, two devices are shown onDie #1 and Die #2, respectively. FIG. 4E shows the process of forming amicro-via 121 on each of these dies while also etching a scribe line 124or dicing line. In an example, the etching of the scribe line 124singulates and relieves stress in the piezoelectric single crystal layer120.

FIGS. 5 to 8 are simplified diagrams illustrating steps for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention. FIG. 5 can represent the method step of formingone or more bond pads 140 and forming a topside metal 141 electricallycoupled to at least one of the bond pads 140. The topside metal 141 caninclude a topside metal plug 146 formed within the topside micro-trench121. In a specific example, the topside metal plug 146 fills the topsidemicro-trench 121 to form a topside portion of a micro-via.

In an example, the bond pads 140 and the topside metal 141 can include agold material or other interconnect metal material depending upon theapplication of the device. These metal materials can be formed by alift-off process, a wet etching process, a dry etching process, ascreen-printing process, an electroplating process, a metal printingprocess, or the like. In a specific example, the deposited metalmaterials can also serve as bond pads for a cap structure, which will bedescribed below.

FIG. 6 can represent a method step for preparing the acoustic resonatordevice for bonding, which can be a hermetic bonding. As shown, a top capstructure is positioned above the partially processed acoustic resonatordevice as described in the previous figures. The top cap structure canbe formed using an interposer substrate 119 in two configurations: fullyprocessed interposer version 601 (through glass via) and partiallyprocessed interposer version 602 (blind via version). In the 601version, the interposer substrate 119 includes through-via structures151 that extend through the interposer substrate 119 and areelectrically coupled to bottom bond pads 142 and top bond pads 143. Inthe 602 version, the interposer substrate 119 includes blind viastructures 152 that only extend through a portion of the interposersubstrate 119 from the bottom side. These blind via structures 152 arealso electrically coupled to bottom bond pads 142. In a specificexample, the interposer substrate can include a silicon, glass,smart-glass, or other like material.

FIG. 7 can represent a method step of bonding the top cap structure tothe partially processed acoustic resonator device. As shown, theinterposer substrate 119 is bonded to the piezoelectric layer by thebond pads (140, 142) and the topside metal 141, which are now denoted asbond pad 144 and topside metal 145. This bonding process can be doneusing a compression bond method or the like. FIG. 8 can represent amethod step of thinning the seed substrate 110, which is now denoted asthinned seed substrate 111. This substrate thinning process can includegrinding and etching processes or the like. In a specific example, thisprocess can include a wafer backgrinding process followed by stressremoval, which can involve dry etching, CMP polishing, or annealingprocesses.

FIG. 9A is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device 901 according to an exampleof the present invention. FIG. 9A can represent a method step forforming backside trenches 113 and 114 to allow access to thepiezoelectric layer from the backside of the thinned seed substrate 111.In an example, the first backside trench 113 can be formed within thethinned seed substrate 111 and underlying the topside metal electrode130. The second backside trench 114 can be formed within the thinnedseed substrate 111 and underlying the topside micro-trench 121 andtopside metal plug 146. This substrate is now denoted thinned substrate112. In a specific example, these trenches 113 and 114 can be formedusing deep reactive ion etching (DRIE) processes, Bosch processes, orthe like. The size, shape, and number of the trenches may vary with thedesign of the acoustic resonator device. In various examples, the firstbackside trench may be formed with a trench shape similar to a shape ofthe topside metal electrode or a shape of the backside metal electrode.The first backside trench may also be formed with a trench shape that isdifferent from both a shape of the topside metal electrode and thebackside metal electrode.

FIGS. 9B and 9C are simplified diagrams illustrating an alternativemethod for conducting the method step as described in FIG. 9A. LikeFIGS. 4D and 4E, these figures can represent the method step ofmanufacturing multiple acoustic resonator devices simultaneously. InFIG. 9B, two devices with cap structures are shown on Die #1 and Die #2,respectively. FIG. 9C shows the process of forming backside trenches(113, 114) on each of these dies while also etching a scribe line 115 ordicing line. In an example, the etching of the scribe line 115 providesan optional way to singulate the backside wafer 112.

FIG. 10 is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device 1000 according to anexample of the present invention. This figure can represent a methodstep of forming a backside metal electrode 131 and a backside metal plug147 within the backside trenches of the thinned seed substrate 112. Inan example, the backside metal electrode 131 can be formed underlyingone or more portions of the thinned substrate 112, within the firstbackside trench 113, and underlying the topside metal electrode 130.This process completes the resonator structure within the acousticresonator device. The backside metal plug 147 can be formed underlyingone or more portions of the thinned substrate 112, within the secondbackside trench 114, and underlying the topside micro-trench 121. Thebackside metal plug 147 can be electrically coupled to the topside metalplug 146 and the backside metal electrode 131. In a specific example,the backside metal electrode 130 can include a molybdenum, aluminum,ruthenium, or titanium material, or the like and combinations thereof.The backside metal plug can include a gold material, low resistivityinterconnect metals, electrode metals, or the like. These layers can bedeposited using the deposition methods described previously.

FIGS. 11A and 11B are simplified diagrams illustrating alternative stepsfor a method of manufacture for an acoustic resonator device accordingto an example of the present invention. These figures show methods ofbonding a backside cap structure underlying the thinned seed substrate112. In FIG. 11A, the backside cap structure is a dry film cap 161,which can include a permanent photo-imageable dry film such as a soldermask, polyimide, or the like. Bonding this cap structure can becost-effective and reliable, but may not produce a hermetic seal. InFIG. 11B, the backside cap structure is a substrate 162, which caninclude a silicon, glass, or other like material. Bonding this substratecan provide a hermetic seal, but may cost more and require additionalprocesses. Depending upon application, either of these backside capstructures can be bonded underlying the first and second backside vias.

FIGS. 12A to 12E are simplified diagrams illustrating steps for a methodof manufacture for an acoustic resonator device according to an exampleof the present invention. More specifically, these figures describeadditional steps for processing the blind via interposer “602” versionof the top cap structure. FIG. 12A shows an acoustic resonator device1201 with blind vias 152 in the top cap structure. In FIG. 12B, theinterposer substrate 119 is thinned, which forms a thinned interposersubstrate 118, to expose the blind vias 152. This thinning process canbe a combination of a grinding process and etching process as describedfor the thinning of the seed substrate. In FIG. 12C, a redistributionlayer (RDL) process and metallization process can be applied to createtop cap bond pads 160 that are formed overlying the blind vias 152 andare electrically coupled to the blind vias 152. As shown in FIG. 12D, aball grid array (BGA) process can be applied to form solder balls 170overlying and electrically coupled to the top cap bond pads 160. Thisprocess leaves the acoustic resonator device ready for wire bonding 171,as shown in FIG. 12E.

FIG. 13 is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention. As shown, device 1300 includes two fullyprocessed acoustic resonator devices that are ready to singulation tocreate separate devices. In an example, the die singulation process canbe done using a wafer dicing saw process, a laser cut singulationprocess, or other processes and combinations thereof.

FIGS. 14A to 14G are simplified diagrams illustrating steps for a methodof manufacture for an acoustic resonator device according to an exampleof the present invention. This method illustrates the process forfabricating an acoustic resonator device similar to that shown in FIG.1B. The method for this example of an acoustic resonator can go throughsimilar steps as described in FIGS. 1-5. FIG. 14A shows where thismethod differs from that described previously. Here, the top capstructure substrate 119 and only includes one layer of metallizationwith one or more bottom bond pads 142. Compared to FIG. 6, there are novia structures in the top cap structure because the interconnectionswill be formed on the bottom side of the acoustic resonator device.

FIGS. 14B to 14F depict method steps similar to those described in thefirst process flow. FIG. 14B can represent a method step of bonding thetop cap structure to the piezoelectric layer 120 through the bond pads(140, 142) and the topside metal 141, now denoted as bond pads 144 andtopside metal 145 with topside metal plug 146. FIG. 14C can represent amethod step of thinning the seed substrate 110, which forms a thinnedseed substrate 111, similar to that described in FIG. 8. FIG. 14D canrepresent a method step of forming first and second backside trenches,similar to that described in FIG. 9A. FIG. 14E can represent a methodstep of forming a backside metal electrode 131 and a backside metal plug147, similar to that described in FIG. 10. FIG. 14F can represent amethod step of bonding a backside cap structure 162, similar to thatdescribed in FIGS. 11A and 11B.

FIG. 14G shows another step that differs from the previously describedprocess flow. Here, the backside bond pads 171, 172, and 173 are formedwithin the backside cap structure 162. In an example, these backsidebond pads 171-173 can be formed through a masking, etching, and metaldeposition processes similar to those used to form the other metalmaterials. A BGA process can be applied to form solder balls 170 incontact with these backside bond pads 171-173, which prepares theacoustic resonator device 1407 for wire bonding.

FIGS. 15A to 15E are simplified diagrams illustrating steps for a methodof manufacture for an acoustic resonator device according to an exampleof the present invention. This method illustrates the process forfabricating an acoustic resonator device similar to that shown in FIG.1B. The method for this example can go through similar steps asdescribed in FIG. 1-5. FIG. 15A shows where this method differs fromthat described previously. A temporary carrier 218 with a layer oftemporary adhesive 217 is attached to the substrate. In a specificexample, the temporary carrier 218 can include a glass wafer, a siliconwafer, or other wafer and the like.

FIGS. 15B to 15F depict method steps similar to those described in thefirst process flow. FIG. 15B can represent a method step of thinning theseed substrate 110, which forms a thinned substrate 111, similar to thatdescribed in FIG. 8. In a specific example, the thinning of the seedsubstrate 110 can include a back side grinding process followed by astress removal process. The stress removal process can include a dryetch, a Chemical Mechanical Planarization (CMP), and annealingprocesses.

FIG. 15C can represent a method step of forming a shared backside trench113, similar to the techniques described in FIG. 9A. The main differenceis that the shared backside trench is configured underlying both topsidemetal electrode 130, topside micro-trench 121, and topside metal plug146. In an example, the shared backside trench 113 is a backsideresonator cavity that can vary in size, shape (all possible geometricshapes), and side wall profile (tapered convex, tapered concave, orright angle). In a specific example, the forming of the shared backsidetrench 113 can include a litho-etch process, which can include aback-to-front alignment and dry etch of the backside substrate 111. Thepiezoelectric layer 120 can serve as an etch stop layer for the formingof the shared backside trench 113.

FIG. 15D can represent a method step of forming a backside metalelectrode 131 and a backside metal 147, similar to that described inFIG. 10. In an example, the forming of the backside metal electrode 131can include a deposition and patterning of metal materials within theshared backside trench 113. Here, the backside metal 131 serves as anelectrode and the backside plug/connect metal 147 within the micro-via121. The thickness, shape, and type of metal can vary as a function ofthe resonator/filter design. As an example, the backside electrode 131and via plug metal 147 can be different metals. In a specific example,these backside metals 131, 147 can either be deposited and patterned onthe surface of the piezoelectric layer 120 or rerouted to the backsideof the substrate 112. In an example, the backside metal electrode may bepatterned such that it is configured within the boundaries of the sharedbackside trench such that the backside metal electrode does not come incontact with one or more side-walls of the seed substrate created duringthe forming of the shared backside trench.

FIG. 15E can represent a method step of bonding a backside cap structure162, similar to that described in FIGS. 11A and 11B, following ade-bonding of the temporary carrier 218 and cleaning of the topside ofthe device to remove the temporary adhesive 217. Those of ordinary skillin the art will recognize other variations, modifications, andalternatives of the methods steps described previously.

As used herein, the term “substrate” can mean the bulk substrate or caninclude overlying growth structures such as an aluminum, gallium, orternary compound of aluminum and gallium and nitrogen containingepitaxial region, or functional regions, combinations, and the like.

One or more benefits are achieved over pre-existing techniques using theinvention. In particular, the present device can be manufactured in arelatively simple and cost effective manner while using conventionalmaterials and/or methods according to one of ordinary skill in the art.Using the present method, one can create a reliable single crystal basedacoustic resonator using multiple ways of three-dimensional stackingthrough a wafer level process. Such filters or resonators can beimplemented in an RF filter device, an RF filter system, or the like.Depending upon the embodiment, one or more of these benefits may beachieved. Of course, there can be other variations, modifications, andalternatives.

With 4G LTE and 5G growing more popular by the day, wireless datacommunication demands high performance RF filters with frequenciesaround 5 GHz and higher. Bulk acoustic wave resonators (BAWR), widelyused in such filters operating at frequencies around 3 GHz and lower,are leading candidates for meeting such demands. Current bulk acousticwave resonators use polycrystalline piezoelectric AlN thin films whereeach grain's c-axis is aligned perpendicular to the film's surface toallow high piezoelectric performance whereas the grains' a- or b-axisare randomly distributed. This peculiar grain distribution works wellwhen the piezoelectric film's thickness is around 1 um and above, whichis the perfect thickness for bulk acoustic wave (BAW) filters operatingat frequencies ranging from 1 to 3 GHz. However, the quality of thepolycrystalline piezoelectric films degrades quickly as the thicknessesdecrease below around 0.5 um, which is required for resonators andfilters operating at frequencies around 5 GHz and above.

Single crystalline or epitaxial piezoelectric thin films grown oncompatible crystalline substrates exhibit good crystalline quality andhigh piezoelectric performance even down to very thin thicknesses, e.g.,0.4 um. The present invention provides manufacturing processes andstructures for high quality bulk acoustic wave resonators with singlecrystalline or epitaxial piezoelectric thin films for high frequency BAWfilter applications.

BAWRs require a piezoelectric material, e.g., AlN, in crystalline form,i.e., polycrystalline or single crystalline. The quality of the filmheavy depends on the chemical, crystalline, or topographical quality ofthe layer on which the film is grown. In conventional BAWR processes(including film bulk acoustic resonator (FBAR) or solidly mountedresonator (SMR) geometry), the piezoelectric film is grown on apatterned bottom electrode, which is usually made of molybdenum (Mo),tungsten (W), or ruthenium (Ru). The surface geometry of the patternedbottom electrode significantly influences the crystalline orientationand crystalline quality of the piezoelectric film, requiring complicatedmodification of the structure.

Thus, the present invention uses single crystalline piezoelectric filmsand thin film transfer processes to produce a BAWR with enhancedultimate quality factor and electro-mechanical coupling for RF filters.Such methods and structures facilitate methods of manufacturing andstructures for RF filters using single crystalline or epitaxialpiezoelectric films to meet the growing demands of contemporary datacommunication.

In an example, the present invention provides transfer structures andprocesses for acoustic resonator devices, which provides a flat,high-quality, single-crystal piezoelectric film for superior acousticwave control and high Q in high frequency. As described above,polycrystalline piezoelectric layers limit Q in high frequency. Also,growing epitaxial piezoelectric layers on patterned electrodes affectsthe crystalline orientation of the piezoelectric layer, which limits theability to have tight boundary control of the resulting resonators.Embodiments of the present invention, as further described below, canovercome these limitations and exhibit improved performance andcost-efficiency.

FIGS. 16A-16C through FIGS. 31A-31C illustrate a method of fabricationfor an acoustic resonator device using a transfer structure with asacrificial layer. In these figure series described below, the “A”figures show simplified diagrams illustrating top cross-sectional viewsof single crystal resonator devices according to various embodiments ofthe present invention. The “B” figures show simplified diagramsillustrating lengthwise cross-sectional views of the same devices in the“A” figures. Similarly, the “C” figures show simplified diagramsillustrating widthwise cross-sectional views of the same devices in the“A” figures. In some cases, certain features are omitted to highlightother features and the relationships between such features. Those ofordinary skill in the art will recognize variations, modifications, andalternatives to the examples shown in these figure series.

FIGS. 16A-16C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a piezoelectric film 1620 overlying a growth substrate 1610. Inan example, the growth substrate 1610 can include silicon (S), siliconcarbide (SiC), or other like materials. The piezoelectric film 1620 canbe an epitaxial film including aluminum nitride (AlN), gallium nitride(GaN), or other like materials. Additionally, this piezoelectricsubstrate can be subjected to a thickness trim.

FIGS. 17A-17C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a first electrode 1710 overlying the surface region of thepiezoelectric film 1620. In an example, the first electrode 1710 caninclude molybdenum (Mo), ruthenium (Ru), tungsten (W), or other likematerials. In a specific example, the first electrode 1710 can besubjected to a dry etch with a slope. As an example, the slope can beabout 60 degrees.

FIGS. 18A-18C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a first passivation layer 1810 overlying the first electrode1710 and the piezoelectric film 1620. In an example, the firstpassivation layer 1810 can include silicon nitride (SiN), silicon oxide(SiO), or other like materials. In a specific example, the firstpassivation layer 1810 can have a thickness ranging from about 50 nm toabout 100 nm.

FIGS. 19A-19C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a sacrificial layer 1910 overlying a portion of the firstelectrode 1810 and a portion of the piezoelectric film 1620. In anexample, the sacrificial layer 1910 can include polycrystalline silicon(poly-Si), amorphous silicon (a-Si), or other like materials. In aspecific example, this sacrificial layer 1910 can be subjected to a dryetch with a slope and be deposited with a thickness of about 1 um.Further, phosphorous doped SiO₂ (PSG) can be used as the sacrificiallayer with different combinations of support layer (e.g., SiN_(X)).

FIGS. 20A-20C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a support layer 2010 overlying the sacrificial layer 1910, thefirst electrode 1710, and the piezoelectric film 1620. In an example,the support layer 2010 can include silicon dioxide (SiO₂), siliconnitride (SiN), or other like materials. In a specific example, thissupport layer 2010 can be deposited with a thickness of about 2-3 um. Asdescribed above, other support layers (e.g., SiN_(X)) can be used in thecase of a PSG sacrificial layer.

FIGS. 21A-21C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step ofpolishing the support layer 2010 to form a polished support layer 2011.In an example, the polishing process can include a chemical-mechanicalplanarization process or the like.

FIGS. 22A-22C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate flipping thedevice and physically coupling overlying the support layer 2011overlying a bond substrate 2210. In an example, the bond substrate 2210can include a bonding support layer 2220 (SiO₂ or like material)overlying a substrate having silicon (Si), sapphire (Al₂O₃), silicondioxide (SiO₂), silicon carbide (SiC), or other like materials. In aspecific embodiment, the bonding support layer 2220 of the bondsubstrate 2210 is physically coupled to the polished support layer 2011.Further, the physical coupling process can include a room temperaturebonding process followed by a 300 degrees Celsius annealing process.

FIGS. 23A-23C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step ofremoving the growth substrate 1610 or otherwise the transfer of thepiezoelectric film 1620. In an example, the removal process can includea grinding process, a blanket etching process, a film transfer process,an ion implantation transfer process, a laser crack transfer process, orthe like and combinations thereof.

FIGS. 24A-24C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming an electrode contact via 2410 within the piezoelectric film 1620(becoming piezoelectric film 1621) overlying the first electrode 1710and forming one or more release holes 2420 within the piezoelectric film1620 and the first passivation layer 1810 overlying the sacrificiallayer 1910. The via forming processes can include various types ofetching processes.

FIGS. 25A-25C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a second electrode 2510 overlying the piezoelectric film 1621.In an example, the formation of the second electrode 2510 includesdepositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other likematerials; and then etching the second electrode 2510 to form anelectrode cavity 2511 and to remove portion 2511 from the secondelectrode to form a top metal 2520. Further, the top metal 2520 isphysically coupled to the first electrode 1720 through electrode contactvia 2410.

FIGS. 26A-26C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a first contact metal 2610 overlying a portion of the secondelectrode 2510 and a portion of the piezoelectric film 1621, and forminga second contact metal 2611 overlying a portion of the top metal 2520and a portion of the piezoelectric film 1621. In an example, the firstand second contact metals can include gold (Au), aluminum (Al), copper(Cu), nickel (Ni), aluminum bronze (AlCu), or related alloys of thesematerials or other like materials.

FIGS. 27A-27C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a second passivation layer 2710 overlying the second electrode2510, the top metal 2520, and the piezoelectric film 1621. In anexample, the second passivation layer 2710 can include silicon nitride(SiN), silicon oxide (SiO_(X)), or other like materials. In a specificexample, the second passivation layer 2710 can have a thickness rangingfrom about 50 nm to about 100 nm.

FIGS. 28A-28C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step ofremoving the sacrificial layer 1910 to form an air cavity 2810. In anexample, the removal process can include a poly-Si etch or an a-Si etch,or the like.

FIGS. 29A-29C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to another exampleof the present invention. As shown, these figures illustrate the methodstep of processing the second electrode 2510 and the top metal 2520 toform a processed second electrode 2910 and a processed top metal 2920.This step can follow the formation of second electrode 2510 and topmetal 2520. In an example, the processing of these two componentsincludes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), orother like materials; and then etching (e.g., dry etch or the like) thismaterial to form the processed second electrode 2910 with an electrodecavity 2912 and the processed top metal 2920. The processed top metal2920 remains separated from the processed second electrode 2910 by theremoval of portion 2911. In a specific example, the processed secondelectrode 2910 is characterized by the addition of an energy confinementstructure configured on the processed second electrode 2910 to increaseQ.

FIGS. 30A-30C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to another exampleof the present invention. As shown, these figures illustrate the methodstep of processing the first electrode 1710 to form a processed firstelectrode 2310. This step can follow the formation of first electrode1710. In an example, the processing of these two components includesdepositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other likematerials; and then etching (e.g., dry etch or the like) this materialto form the processed first electrode 3010 with an electrode cavity,similar to the processed second electrode 2910. Air cavity 2811 showsthe change in cavity shape due to the processed first electrode 3010. Ina specific example, the processed first electrode 3010 is characterizedby the addition of an energy confinement structure configured on theprocessed second electrode 3010 to increase Q.

FIGS. 31A-31C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to another exampleof the present invention. As shown, these figures illustrate the methodstep of processing the first electrode 1710, to form a processed firstelectrode 2310, and the second electrode 2510/top metal 2520 to form aprocessed second electrode 2910/processed top metal 2920. These stepscan follow the formation of each respective electrode, as described forFIGS. 29A-29C and 30A-30C. Those of ordinary skill in the art willrecognize other variations, modifications, and alternatives.

FIGS. 32A-32C through FIGS. 46A-46C illustrate a method of fabricationfor an acoustic resonator device using a transfer structure withoutsacrificial layer. In these figure series described below, the “A”figures show simplified diagrams illustrating top cross-sectional viewsof single crystal resonator devices according to various embodiments ofthe present invention. The “B” figures show simplified diagramsillustrating lengthwise cross-sectional views of the same devices in the“A” figures. Similarly, the “C” figures show simplified diagramsillustrating widthwise cross-sectional views of the same devices in the“A” figures. In some cases, certain features are omitted to highlightother features and the relationships between such features. Those ofordinary skill in the art will recognize variations, modifications, andalternatives to the examples shown in these figure series.

FIGS. 32A-32C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming apiezoelectric film 3220 overlying a growth substrate 3210. In anexample, the growth substrate 3210 can include silicon (S), siliconcarbide (SiC), or other like materials. The piezoelectric film 3220 canbe an epitaxial film including aluminum nitride (AlN), gallium nitride(GaN), or other like materials. Additionally, this piezoelectricsubstrate can be subjected to a thickness trim.

FIGS. 33A-33C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming a firstelectrode 3310 overlying the surface region of the piezoelectric film3220. In an example, the first electrode 3310 can include molybdenum(Mo), ruthenium (Ru), tungsten (W), or other like materials. In aspecific example, the first electrode 3310 can be subjected to a dryetch with a slope. As an example, the slope can be about 60 degrees.

FIGS. 34A-34C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming a firstpassivation layer 3410 overlying the first electrode 3310 and thepiezoelectric film 3220. In an example, the first passivation layer 3410can include silicon nitride (SiN), silicon oxide (SiO_(X)), or otherlike materials. In a specific example, the first passivation layer 3410can have a thickness ranging from about 50 nm to about 100 nm.

FIGS. 35A-35C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming a supportlayer 3510 overlying the first electrode 3310, and the piezoelectricfilm 3220. In an example, the support layer 3510 can include silicondioxide (SiO₂), silicon nitride (SiN), or other like materials. In aspecific example, this support layer 3510 can be deposited with athickness of about 2-3 um. As described above, other support layers(e.g., SiN_(X)) can be used in the case of a PSG sacrificial layer.

FIGS. 36A-36C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the optional method step of processingthe support layer 3510 (to form support layer 3511) in region 3610. Inan example, the processing can include a partial etch of the supportlayer 3510 to create a flat bond surface. In a specific example, theprocessing can include a cavity region. In other examples, this step canbe replaced with a polishing process such as a chemical-mechanicalplanarization process or the like.

FIGS. 37A-37C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming an air cavity3710 within a portion of the support layer 3511 (to form support layer3512). In an example, the cavity formation can include an etchingprocess that stops at the first passivation layer 3410.

FIGS. 38A-38C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming one or morecavity vent holes 3810 within a portion of the piezoelectric film 3220through the first passivation layer 3410. In an example, the cavity ventholes 3810 connect to the air cavity 3710.

FIGS. 39A-39C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate flipping the device and physicallycoupling overlying the support layer 3512 overlying a bond substrate3910. In an example, the bond substrate 3910 can include a bondingsupport layer 3920 (SiO₂ or like material) overlying a substrate havingsilicon (Si), sapphire (Al₂O₃), silicon dioxide (SiO₂), silicon carbide(SiC), or other like materials. In a specific embodiment, the bondingsupport layer 3920 of the bond substrate 3910 is physically coupled tothe polished support layer 3512. Further, the physical coupling processcan include a room temperature bonding process followed by a 300 degreesCelsius annealing process.

FIGS. 40A-40C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of removing the growthsubstrate 3210 or otherwise the transfer of the piezoelectric film 3220.In an example, the removal process can include a grinding process, ablanket etching process, a film transfer process, an ion implantationtransfer process, a laser crack transfer process, or the like andcombinations thereof.

FIGS. 41A-41C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming an electrodecontact via 4110 within the piezoelectric film 3220 overlying the firstelectrode 3310. The via forming processes can include various types ofetching processes.

FIGS. 42A-42C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming a secondelectrode 4210 overlying the piezoelectric film 3220. In an example, theformation of the second electrode 4210 includes depositing molybdenum(Mo), ruthenium (Ru), tungsten (W), or other like materials; and thenetching the second electrode 4210 to form an electrode cavity 4211 andto remove portion 4211 from the second electrode to form a top metal4220. Further, the top metal 4220 is physically coupled to the firstelectrode 3310 through electrode contact via 4110.

FIGS. 43A-43C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to an example of the present invention. Asshown, these figures illustrate the method step of forming a firstcontact metal 4310 overlying a portion of the second electrode 4210 anda portion of the piezoelectric film 3220, and forming a second contactmetal 4311 overlying a portion of the top metal 4220 and a portion ofthe piezoelectric film 3220. In an example, the first and second contactmetals can include gold (Au), aluminum (Al), copper (Cu), nickel (Ni),aluminum bronze (AlCu), or other like materials. This figure also showsthe method step of forming a second passivation layer 4320 overlying thesecond electrode 4210, the top metal 4220, and the piezoelectric film3220. In an example, the second passivation layer 4320 can includesilicon nitride (SiN), silicon oxide (SiO_(X)), or other like materials.In a specific example, the second passivation layer 4320 can have athickness ranging from about 50 nm to about 100 nm.

FIGS. 44A-44C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process for single crystal acousticresonator devices according to another example of the present invention.As shown, these figures illustrate the method step of processing thesecond electrode 4210 and the top metal 4220 to form a processed secondelectrode 4410 and a processed top metal 4420. This step can follow theformation of second electrode 4210 and top metal 4220. In an example,the processing of these two components includes depositing molybdenum(Mo), ruthenium (Ru), tungsten (W), or other like materials; and thenetching (e.g., dry etch or the like) this material to form the processedsecond electrode 4410 with an electrode cavity 4412 and the processedtop metal 4420. The processed top metal 4420 remains separated from theprocessed second electrode 4410 by the removal of portion 4411. In aspecific example, the processed second electrode 4410 is characterizedby the addition of an energy confinement structure configured on theprocessed second electrode 4410 to increase Q.

FIGS. 45A-45C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to another exampleof the present invention. As shown, these figures illustrate the methodstep of processing the first electrode 3310 to form a processed firstelectrode 4510. This step can follow the formation of first electrode3310. In an example, the processing of these two components includesdepositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other likematerials; and then etching (e.g., dry etch or the like) this materialto form the processed first electrode 4510 with an electrode cavity,similar to the processed second electrode 4410. Air cavity 3711 showsthe change in cavity shape due to the processed first electrode 4510. Ina specific example, the processed first electrode 4510 is characterizedby the addition of an energy confinement structure configured on theprocessed second electrode 4510 to increase Q.

FIGS. 46A-46C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process using a sacrificial layer forsingle crystal acoustic resonator devices according to another exampleof the present invention. As shown, these figures illustrate the methodstep of processing the first electrode 3310, to form a processed firstelectrode 4510, and the second electrode 4210/top metal 4220 to form aprocessed second electrode 4410/processed top metal 4420. These stepscan follow the formation of each respective electrode, as described forFIGS. 44A-44C and 45A-45C. Those of ordinary skill in the art willrecognize other variations, modifications, and alternatives.

FIGS. 47A-47C through FIGS. 59A-59C illustrate a method of fabricationfor an acoustic resonator device using a transfer structure with amultilayer mirror structure. In these figure series described below, the“A” figures show simplified diagrams illustrating top cross-sectionalviews of single crystal resonator devices according to variousembodiments of the present invention. The “B” figures show simplifieddiagrams illustrating lengthwise cross-sectional views of the samedevices in the “A” figures. Similarly, the “C” figures show simplifieddiagrams illustrating widthwise cross-sectional views of the samedevices in the “A” figures. In some cases, certain features are omittedto highlight other features and the relationships between such features.Those of ordinary skill in the art will recognize variations,modifications, and alternatives to the examples shown in these figureseries.

FIGS. 47A-47C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a piezoelectric film 4720 overlying a growth substrate 4710. Inan example, the growth substrate 4710 can include silicon (S), siliconcarbide (SiC), or other like materials. The piezoelectric film 4720 canbe an epitaxial film including aluminum nitride (AlN), gallium nitride(GaN), or other like materials. Additionally, this piezoelectricsubstrate can be subjected to a thickness trim.

FIGS. 48A-48C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a first electrode 4810 overlying the surface region of thepiezoelectric film 4720. In an example, the first electrode 4810 caninclude molybdenum (Mo), ruthenium (Ru), tungsten (W), or other likematerials. In a specific example, the first electrode 4810 can besubjected to a dry etch with a slope. As an example, the slope can beabout 60 degrees.

FIGS. 49A-49C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a multilayer mirror or reflector structure. In an example, themultilayer mirror includes at least one pair of layers with a lowimpedance layer 4910 and a high impedance layer 4920. In FIGS. 49A-49C,two pairs of low/high impedance layers are shown (low: 4910 and 4911;high: 4920 and 4921). In an example, the mirror/reflector area can belarger than the resonator area and can encompass the resonator area. Ina specific embodiment, each layer thickness is about ¼ of the wavelengthof an acoustic wave at a targeting frequency. The layers can bedeposited in sequence and be etched afterwards, or each layer can bedeposited and etched individually. In another example, the firstelectrode 4810 can be patterned after the mirror structure is patterned.

FIGS. 50A-50C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a support layer 5010 overlying the mirror structure (layers4910, 4911, 4920, and 4921), the first electrode 4810, and thepiezoelectric film 4720. In an example, the support layer 5010 caninclude silicon dioxide (SiO₂), silicon nitride (SiN), or other likematerials. In a specific example, this support layer 5010 can bedeposited with a thickness of about 2-3 um. As described above, othersupport layers (e.g., SiN_(X)) can be used.

FIGS. 51A-51C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step ofpolishing the support layer 5010 to form a polished support layer 5011.In an example, the polishing process can include a chemical-mechanicalplanarization process or the like.

FIGS. 52A-52C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate flipping thedevice and physically coupling overlying the support layer 5011overlying a bond substrate 5210. In an example, the bond substrate 5210can include a bonding support layer 5220 (SiO₂ or like material)overlying a substrate having silicon (Si), sapphire (Al₂O₃), silicondioxide (SiO₂), silicon carbide (SiC), or other like materials. In aspecific embodiment, the bonding support layer 5220 of the bondsubstrate 5210 is physically coupled to the polished support layer 5011.Further, the physical coupling process can include a room temperaturebonding process followed by a 300 degrees Celsius annealing process.

FIGS. 53A-53C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step ofremoving the growth substrate 4710 or otherwise the transfer of thepiezoelectric film 4720. In an example, the removal process can includea grinding process, a blanket etching process, a film transfer process,an ion implantation transfer process, a laser crack transfer process, orthe like and combinations thereof.

FIGS. 54A-54C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming an electrode contact via 5410 within the piezoelectric film 4720overlying the first electrode 4810. The via forming processes caninclude various types of etching processes.

FIGS. 55A-55C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a second electrode 5510 overlying the piezoelectric film 4720.In an example, the formation of the second electrode 5510 includesdepositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other likematerials; and then etching the second electrode 5510 to form anelectrode cavity 5511 and to remove portion 5511 from the secondelectrode to form a top metal 5520. Further, the top metal 5520 isphysically coupled to the first electrode 5520 through electrode contactvia 5410.

FIGS. 56A-56C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to an example of thepresent invention. As shown, these figures illustrate the method step offorming a first contact metal 5610 overlying a portion of the secondelectrode 5510 and a portion of the piezoelectric film 4720, and forminga second contact metal 5611 overlying a portion of the top metal 5520and a portion of the piezoelectric film 4720. In an example, the firstand second contact metals can include gold (Au), aluminum (Al), copper(Cu), nickel (Ni), aluminum bronze (AlCu), or other like materials. Thisfigure also shows the method step of forming a second passivation layer5620 overlying the second electrode 5510, the top metal 5520, and thepiezoelectric film 4720. In an example, the second passivation layer5620 can include silicon nitride (SiN), silicon oxide (SiO_(X)), orother like materials. In a specific example, the second passivationlayer 5620 can have a thickness ranging from about 50 nm to about 100nm.

FIGS. 57A-57C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to another exampleof the present invention. As shown, these figures illustrate the methodstep of processing the second electrode 5510 and the top metal 5520 toform a processed second electrode 5710 and a processed top metal 5720.This step can follow the formation of second electrode 5710 and topmetal 5720. In an example, the processing of these two componentsincludes depositing molybdenum (Mo), ruthenium (Ru), tungsten (W), orother like materials; and then etching (e.g., dry etch or the like) thismaterial to form the processed second electrode 5410 with an electrodecavity 5712 and the processed top metal 5720. The processed top metal5720 remains separated from the processed second electrode 5710 by theremoval of portion 5711. In a specific example, this processing givesthe second electrode and the top metal greater thickness while creatingthe electrode cavity 5712. In a specific example, the processed secondelectrode 5710 is characterized by the addition of an energy confinementstructure configured on the processed second electrode 5710 to increaseQ.

FIGS. 58A-58C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to another exampleof the present invention. As shown, these figures illustrate the methodstep of processing the first electrode 4810 to form a processed firstelectrode 5810. This step can follow the formation of first electrode4810. In an example, the processing of these two components includesdepositing molybdenum (Mo), ruthenium (Ru), tungsten (W), or other likematerials; and then etching (e.g., dry etch or the like) this materialto form the processed first electrode 5810 with an electrode cavity,similar to the processed second electrode 5710. Compared to the twoprevious examples, there is no air cavity. In a specific example, theprocessed first electrode 5810 is characterized by the addition of anenergy confinement structure configured on the processed secondelectrode 5810 to increase Q.

FIGS. 59A-59C are simplified diagrams illustrating variouscross-sectional views of a single crystal acoustic resonator device andof method steps for a transfer process with a multilayer mirror forsingle crystal acoustic resonator devices according to another exampleof the present invention. As shown, these figures illustrate the methodstep of processing the first electrode 4810, to form a processed firstelectrode 5810, and the second electrode 5510/top metal 5520 to form aprocessed second electrode 5710/processed top metal 5720. These stepscan follow the formation of each respective electrode, as described forFIGS. 57A-57C and 58A-58C. Those of ordinary skill in the art willrecognize other variations, modifications, and alternatives.

In each of the preceding examples relating to transfer processes, energyconfinement structures can be formed on the first electrode, secondelectrode, or both. In an example, these energy confinement structuresare mass loaded areas surrounding the resonator area. The resonator areais the area where the first electrode, the piezoelectric layer, and thesecond electrode overlap. The larger mass load in the energy confinementstructures lowers a cut-off frequency of the resonator. The cut-offfrequency is the lower or upper limit of the frequency at which theacoustic wave can propagate in a direction parallel to the surface ofthe piezoelectric film. Therefore, the cut-off frequency is theresonance frequency in which the wave is travelling along the thicknessdirection and thus is determined by the total stack structure of theresonator along the vertical direction. In piezoelectric films (e.g.,AlN), acoustic waves with lower frequency than the cut-off frequency canpropagate in a parallel direction along the surface of the film, i.e.,the acoustic wave exhibits a high-band-cut-off type dispersioncharacteristic. In this case, the mass loaded area surrounding theresonator provides a barrier preventing the acoustic wave frompropagating outside the resonator. By doing so, this feature increasesthe quality factor of the resonator and improves the performance of theresonator and, consequently, the filter.

In addition, the top single crystalline piezoelectric layer can bereplaced by a polycrystalline piezoelectric film. In such films, thelower part that is close to the interface with the substrate has poorcrystalline quality with smaller grain sizes and a wider distribution ofthe piezoelectric polarization orientation than the upper part of thefilm close to the surface. This is due to the polycrystalline growth ofthe piezoelectric film, i.e., the nucleation and initial film haverandom crystalline orientations. Considering AlN as a piezoelectricmaterial, the growth rate along the c-axis or the polarizationorientation is higher than other crystalline orientations that increasethe proportion of the grains with the c-axis perpendicular to the growthsurface as the film grows thicker. In a typical polycrystalline AlN filmwith about a 1 um thickness, the upper part of the film close to thesurface has better crystalline quality and better alignment in terms ofpiezoelectric polarization. By using the thin film transfer processcontemplated in the present invention, it is possible to use the upperportion of the polycrystalline film in high frequency BAW resonatorswith very thin piezoelectric films. This can be done by removing aportion of the piezoelectric layer during the growth substrate removalprocess. Of course, there can be other variations, modifications, andalternatives.

In an example, the present invention provides a high-performance,ultra-small pass-band Bulk Acoustic Wave (BAW) Radio Frequency (RF)Diplexer for use in 5 and 6 GHz Wi-Fi applications. This diplexercircuit device can be configured with two passbands, a first passbandcovering U-NII-1 through U-NII-3 and a second passband covering U-NII-5through U-NII-8 bands, and at least two stopbands, a first stopbandrejecting at least a portion of signals in the U-NII-5 through U-NII-8bands and a second stopband rejecting at least a portion of signalsbelow in the U-NII-1 through U-NII-3 bands. Further details of thesebands are shown in FIG. 60.

FIG. 60 is a simplified diagram illustrating filter pass-bandrequirements in a radio frequency spectrum according to an example ofthe present invention. As shown, the frequency spectrum 6000 shows arange from about 3.3 GHz to about 7.125 GHz. Here, a first applicationband (3.3 GHz-4.2 GHz) 6010 is configured for 5G n77 applications. Thisband includes a 5G sub-band (3.3 GHz-3.8 GHz) 6011, which includesfurther LTE sub-bands (3.4 GHz-3.6 GHz) 6012, B43 (3.6 GHz-3.8 GHz)6013, and CBRS (3.55 GHz-3.7 GHz) 6014. The CBRS band 6014 covers theCBRS LTE B48 and B49 bands. A second application band (4.4 GHz-5.0 GHz)6020 is configured for 5G n79 applications. Those of ordinary skill inthe art will recognize other variations, modifications, andalternatives.

A third application band 6030, labeled (5.15 GHz-5.925), can beconfigured for the 5.5 GHz Wi-Fi and 5G applications. In an example,this band can include a B252 sub-band (5.15 GHz-5.25 GHz) 6031, a B255sub-band (5.735 GHz-5850 GHz) 6032, and a B47 sub-band (5.855 GHz-5.925GHz) 6033. These sub-bands can be configured alongside a UNII-1 band(5.15 GHz-5.25 GHz) 6034, a UNII-2A band (5.25 GHz-5.33 GHz) 6035, aUNII-2C band (5.49 GHz-5.735 GHz) 6036, a UNII-3 band (5.725 GHz-5.835GHz) 6037, and a UNII-4 band (5.85 GHz-5.925 GHz) 6038. These bands cancoexist with additional bands configured following the third applicationband 6030 for other applications. In an example, there can be a UNII-5band (5.925 GHz-6.425 GHz) 6040, a UNII-6 band (6.425 GHz-6.525 GHz)6050, a UNII-7 band (6.525 GHz-6875 GHz) 6060, and a UNII-8 band (6.875GHz-7.125 GHz) 6070. Of course, there can be other variations,modifications, and alternatives.

In an embodiment, the present diplexer utilizes high puritypiezoelectric XBAW technology, as described in the previous figures,which provides leading RF diplexer performance. This filter provides lowinsertion loss across U-NII-1 through U-NII-3 bands and U-NII-5 throughU-NII-8 bands and meets the stringent rejection requirements enablingcoexistence with U-NII-1 through U-NII-3 bands and U-NII-5 throughU-NII-8 bands. The high-power rating satisfies the demanding powerrequirements of the latest Wi-Fi (e.g., Wi-Fi6E) and 5G standards.

FIG. 61 is a simplified diagram illustrating an overview of key marketsthat are applications for acoustic wave RF filters according to anexample of the present invention. The application chart 6100 for 5.5 GHzBAW RF filters shows mobile devices, smartphones, automobiles, Wi-Fitri-band routers, tri-band mobile devices, tri-band smartphones,integrated cable modems, Wi-Fi tri-band access points, 5G small cells,and the like. A schematic representation of the frequency spectrum usedin a Wi-Fi/5G system is provided in FIG. 62.

FIG. 62 is a simplified diagram illustrating application areas for RFfilters in Tri-Band Wi-Fi radios according to examples of the presentinvention. As shown, RF filters used by communication devices 6210 canbe configured for specific applications at three separate bands ofoperation. In a specific example, application area 6220 operates at 2.4GHz and includes computing and mobile devices, application area 6230operates at 5.5/5.6 GHz and includes television and display devices, andapplication area 6240 operates at 6.5/6.6 GHz and includes video gameconsole and handheld devices. Those of ordinary skill in the art willrecognize other variations, modifications, and alternatives.

The present invention includes resonator and RF filter devices usingboth textured polycrystalline materials (deposited using PVD methods)and single crystal piezoelectric materials (grown using CVD techniqueupon a seed substrate). Various substrates can be used for fabricatingthe acoustic devices, such silicon substrates of variouscrystallographic orientations and the like. Additionally, the presentmethod can use sapphire substrates, silicon carbide substrates, galliumnitride (GaN) bulk substrates, or aluminum nitride (AlN) bulksubstrates. The present method can also use GaN templates, AlNtemplates, and Al_(x)Ga_(1-x)N templates (where x varies between 0.0 and1.0). These substrates and templates can have polar, non-polar, orsemi-polar crystallographic orientations. Further the piezoelectricmaterials deposed on the substrate can include allows selected from atleast one of the following: AlN, AlGaN, MgHfAlN, GaN, InN, InGaN, AlInN,AlInGaN, ScAlN, ScAlGaN, ScGaN, ScN, BAlN, BAlScN, and BN.

The resonator and filter devices may employ process technologiesincluding but not limited to Solidly-Mounted Resonator (SMR), Film BulkAcoustic Resonator (FBAR), or XBAW technology. Representativecross-sections are shown below in FIGS. 63A-63C. For clarification, theterms “top” and “bottom” used in the present specification are notgenerally terms in reference of a direction of gravity. Rather, theterms “top” and “bottom” are used in reference to each other in thecontext of the present device and related circuits. Those of ordinaryskill in the art will recognize other variations, modifications, andalternatives.

In an example, the piezoelectric layer ranges between 0.1 and 2.0 um andis optimized to produced optimal combination of resistive and acousticlosses. The thickness of the top and bottom electrodes range can between250 Å and 2500 Å and the metal consists of a refractory metal with highacoustic velocity and low resistivity. In a specific example, theresonators can be “passivated” with a dielectric (not shown in FIGS.63A-63C) consisting of a nitride and or an oxide and whose range isbetween 100 Å and 2000 Å. In this case, the dielectric layer is used toadjust resonator resonance frequency. Extra care is taken to reduce themetal resistivity between adjacent resonators on a metal layer calledthe interconnect metal. The thickness of the interconnect metal canrange between 500 Å and 5 um. The resonators contain at least one aircavity interface in the case of SMRs and two air cavity interfaces inthe case of FBARs and XBAWs. In an example, the shape of the resonatorscan be selected from asymmetrical shapes including ellipses, rectangles,and polygons, and the like. Further, the resonators contain reflectingfeatures near the resonator edge on one or both sides of the resonator.

FIGS. 63A-63C are simplified diagrams illustrating cross-sectional viewsof resonator devices according to various examples of the presentinvention. More particularly, device 6301 of FIG. 63A shows a BAWresonator device including an SMR, FIG. 63B shows a BAW resonator deviceincluding an FBAR, and FIG. 63C shows a BAW resonator device with a highpurity XBAW. As shown in SMR device 6301, a reflector device 6320 isconfigured overlying a substrate member 6310. The reflector device 6320can be a Bragg reflector or the like. A bottom electrode 6330 isconfigured overlying the reflector device 6320. A polycrystallinepiezoelectric layer 6340 is configured overlying the bottom electrode6330. Further, a top electrode 6350 is configured overlying thepolycrystalline layer 6340. As shown in the FBAR device 6302, thelayered structure including the bottom electrode 6330, thepolycrystalline layer 6340, and the top electrode 6350 remains the same.The substrate member 6311 includes an air cavity 6312, and a dielectriclayer is formed overlying the substrate member 6311 and covering the aircavity 6312. As shown in XBAW device 6303, the substrate member 6311also contains an air cavity 6312, but the bottom electrode 6330 isformed within a region of the air cavity 6312. A high puritypiezoelectric layer 6341 is formed overlying the substrate member 6311,the air cavity 6312, and the bottom electrode 6341. Further, a topelectrode 6350 is formed overlying a portion of the high puritypiezoelectric layer 6341. This high purity piezoelectric layer 6341 caninclude piezoelectric materials as described throughout thisspecification. These resonators can be scaled and configured intocircuit configurations shown in FIGS. 65A-65C.

FIG. 64A is a simplified circuit diagram of a diplexer device accordingto an example of the present invention. As shown, device 6401 includes afirst BAW resonator device 6411 and a second BAW resonator device 6412.Each of these BAW resonator devices have inductors coupled of both ends(inductors 6421 and 6423 coupled to the first BAW resonator 6411; andinductors 6422 and 6424 coupled to the second BAW resonator 6412).Inductors 6423 and 6424 are also coupled to a common node, which is alsocoupled to another inductor 6425. A first port (P1) 6441 is coupled toinductor 6421 and a second port (P2) 6442 is coupled to the BAWresonator device 6410. A third port, which can be an antenna port, iscoupled to inductor 6425. Those of ordinary skill in the art willrecognize other variations, modifications, and alternatives.

In an example, the present invention provides an RF diplexer circuitdevice. The diplexer can include a first filter circuit and a secondfilter circuit coupled to a multiplexer or inductor device. The firstfilter circuit can be configured to receive a first input signal and toproduce a first filtered signal, while the second filter circuitconfigured to receive a second input signal and to produce a secondfiltered signal. Each of these filter circuits includes a plurality ofseries resonators and a plurality of shunt resonators. The multiplexeror inductor device is coupled to the first filter circuit and the secondfilter circuit and can be configured to select between the firstfiltered signal and the second filtered signal. An example inductorconfiguration is shown in FIG. 64B.

In an example, the resonators of the first and second filter devices canbe configured in ladder configuration. In this case, the plurality ofseries resonators is configured in a serial configuration and theplurality of shunt resonators is configured in a parallel configuration.In a specific example, the serial configuration forms a resonanceprofile and an anti-resonance profile. The parallel configuration alsoforms a resonance profile and an anti-resonance profile. These profilesare such that the resonance profile from the serial configuration isoff-set with the anti-resonance profile of the parallel configuration toform the pass-band.

In an example, the resonators of the first and second filter devices canbe configured in a lattice configuration. In this case, the plurality ofseries resonators includes a first plurality configured in a firstserial configuration and a second plurality configured in a secondserial configuration. The plurality of shunt resonators includes aplurality of shunt resonator pairs, each of which are cross-coupledbetween one of the first plurality of series resonators in the firstserial configuration and one of the second plurality of seriesresonators in the second serial configuration. In a specific example,this lattice configuration can include a plurality of baluns orinductors, each of which is coupled between the first and second serialconfigurations and configured between each of the plurality of shuntresonator pairs.

FIG. 64B is a simplified circuit diagram of a diplexer device accordingto an example of the present invention. As shown, device 6402 includes afirst BAW resonator device 6441 and a second BAW resonator device 6442.Each of these BAW resonator devices have inductors coupled of both ends(inductors 6451 and 6453 coupled to the first BAW resonator 6441; andinductors 6452 and 6454 coupled to the second BAW resonator 6442).Inductors 6453 and 6454 are also coupled to a common node, which is alsocoupled to another inductor 6445. A first port (P1) 6431 is coupled toinductor 6451 and a second port (P2) 6432 is coupled to inductor 6452. Athird port (P3) 6433, which can be an antenna port, is coupled toinductor 6455. The topologies of the filter circuits 6411/6412 of FIG.64A and resonator devices 6441/6442 in FIG. 64B can include thosediscussed below.

The RF filter circuit can comprise various circuit topologies, includingmodified lattice (“I”) 6501, lattice (“II”) 6502, and ladder (“III”)6503 circuit configurations, as shown in FIGS. 65A, 65B, and 65C,respectively. These figures are representative lattice and ladderdiagrams for acoustic filter designs including resonators and otherpassive components. The lattice and modified lattice configurationsinclude differential input ports 6510 and differential output ports6550, while the ladder configuration includes a single-ended input port6511 and a single-ended output port 6550. In the lattice configurations,nodes are denoted by top nodes (t1-t3) and bottom nodes (b1-b3), whilein the ladder configuration the nodes are denoted as one set of nodes(n1-n4). The series resonator elements (in cases I, II, and III) areshown with white center elements 6521-6524 and the shunt resonatorelements have darkened center circuit elements 6531-6534. The modifiedlattice circuit diagram (FIG. 65A) includes inductors 6541-6543. Thefilter circuit contains resonators with at least two resonancefrequencies. The center of the pass-band frequency can be adjusted by atrimming step (using an ion milling technique or other like technique)and the shape the filter skirt can be adjusted by trimming individualresonator elements (to vary the resonance frequency of one or moreelements) in the circuit. The BAW resonators with their sharp impedancevariations over frequency can be responsible for the high filtersteepness of the filter circuit device.

In an example, the inductors and capacitors shown in FIGS. 64B and65A-65C and any other matching elements can be realized on-chip (inproximity to the resonator elements) or off-chip (nearby to theresonator chip) and can be used to adjust frequency pass-band and/ormatching of impedance (to achieve the return loss specification) for thefilter circuit. Furthermore, inductors in the shunt resonator paths canbe used as additional design parameters. In various examples, this hasproven to be especially effective to control the wideband response ofthe filter for high rejection.

Additionally, Surface Mount Device (SMD) components, such as inductorsand capacitors, can be employed externally to the device to improve itsoverall electrical performance. In FIG. 64B, these elements arerepresented as series inductors at the filter input and output. Ofcourse, there can be variations, modifications, and alternatives.

In an example, the present invention provides an RF filter circuitdevice using a ladder configuration including a plurality of resonatordevices and a plurality of shunt configuration resonator devices. Eachof the plurality of resonator devices includes at least a capacitordevice, a bottom electrode, a piezoelectric material, a top electrode,and an insulating material configured in accordance to any of theresonator examples described previously. The plurality of resonatordevices is configured in a serial configuration, while the plurality ofshunt configuration resonators is configured in a parallel configurationsuch that one of the plurality of shunt configuration resonators iscoupled to the serial configuration following each of the plurality ofresonator devices.

In an example, the RF filter circuit device in a ladder configurationcan also be described as follows. The device can include an input port,a first node coupled to the input port, a first resonator coupledbetween the first node and the input port. A second node is coupled tothe first node and a second resonator is coupled between the first nodeand the second node. A third node is coupled to the second node and athird resonator is coupled between the second node and the third node. Afourth node is coupled to the third node and a fourth resonator iscoupled between the third node and the output port. Further, an outputport is coupled to the fourth node. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

Each of the first, second, third, and fourth resonators can include acapacitor device. Each such capacitor device can include a substratemember, which has a cavity region and an upper surface region contiguouswith an opening in the first cavity region. Each capacitor device caninclude a bottom electrode within a portion of the cavity region and apiezoelectric material overlying the upper surface region and the bottomelectrode. Also, each capacitor device can include a top electrodeoverlying the piezoelectric material and the bottom electrode, as wellas an insulating material overlying the top electrode and configuredwith a thickness to tune the resonator.

The diplexer device includes a first filter device and a second filterdevice. In a ladder configuration, each filter device includes a serialconfiguration a parallel configuration. Further, a first circuitresponse can be configured between the first input port and the outputport and configured from the serial and parallel configurations of thefirst filter device to achieve a first transmission loss from a firstpass-band and a second circuit response can be configured between thesecond input port and the output port and configured from the serial andparallel configurations of the second filter device to achieve a secondtransmission loss from a second pass-band.

In an example, the first pass-band has a characteristic frequencycentered around 5.4925 GHz and having a bandwidth from 5.150 GHz to5.835 GHz such that the characteristic frequency centered around 5.4925GHz is tuned from a lower frequency ranging from about 4.9 GHz to 5.4GHz. In this case, the second pass-band has a characteristic frequencycentered around 6.535 GHz and having a bandwidth from 5.945 GHz to 7.125GHz such that the characteristic frequency centered around 6.535 GHz istuned from a lower frequency ranging from about 5.9 GHz to 6.4 GHz.

In an example, the first pass-band has a characteristic frequencycentered around 5.5225 GHz and having a bandwidth from 5.150 GHz to5.895 GHz such that the characteristic frequency centered around 5.5225GHz is tuned from a lower frequency ranging from about 4.9 GHz to 5.4GHz. In this case, the second pass-band has a characteristic frequencycentered around 6.615 GHz and having a bandwidth from 6.105 GHz to 7.125GHz such that the characteristic frequency centered around 6.535 GHz istuned from a lower frequency ranging from about 5.9 GHz to 6.4 GHz.

In an example, the piezoelectric materials can include single crystalmaterials, polycrystalline materials, or combinations thereof and thelike. The piezoelectric materials can also include a substantiallysingle crystal material that exhibits certain polycrystalline qualities,i.e., an essentially single crystal material. In a specific example, thefirst, second, third, and fourth piezoelectric materials are eachessentially a single crystal aluminum nitride (AlN) bearing material oraluminum scandium nitride (AlScN) bearing material, a single crystalgallium nitride (GaN) bearing material or gallium aluminum nitride(GaAlN) bearing material, a magnesium hafnium aluminum nitride (MgHfAlN)material, or the like. In other specific examples, these piezoelectricmaterials each comprise a polycrystalline aluminum nitride (AlN) bearingmaterial or aluminum scandium nitride (AlScN) bearing material, or apolycrystalline gallium nitride (GaN) bearing material or galliumaluminum nitride (GaAlN) bearing material, a magnesium hafnium aluminumnitride (MgHfAlN) material, or the like. In other examples, thepiezoelectric materials can include aluminum gallium nitride(Al_(x)Ga_(1-x)N) material or an aluminum scandium nitride(Al_(x)Sc_(1-x)N) material characterized by a composition of 0≤X<1.0. Asdiscussed previously, the thicknesses of the piezoelectric materials canvary, and in some cases can be greater than 250 nm.

In a specific example, the piezoelectric material can be configured as alayer characterized by an x-ray diffraction (XRD) rocking curve fullwidth at half maximum ranging from 0 degrees to 2 degrees. The x-rayrocking curve FWHM parameter can depend on the combination of materialsused for the piezoelectric layer and the substrate, as well as thethickness of these materials. Further, an FWHM profile is used tocharacterize material properties and surface integrity features, and isan indicator of crystal quality/purity. The acoustic resonator devicesusing single crystal materials exhibit a lower FWHM compared to devicesusing polycrystalline material, i.e., single crystal materials have ahigher crystal quality or crystal purity.

In a specific example, the serial configuration forms a resonanceprofile and an anti-resonance profile. The parallel configuration alsoforms a resonance profile and an anti-resonance profile. These profilesare such that the resonance profile from the serial configuration isoff-set with the anti-resonance profile of the parallel configuration toform the pass-band.

In a specific example, the each of the pass-bands is characterized by aband edge on each side of the pass-band and having an amplitudedifference ranging from 10 dB to 60 dB. Each of the pass-bands has apair of band edges; each of which has a transition region from thepass-band to a stop band such that the transition region is no greaterthan 250 MHz. In another example, each of the pass-bands can include apair of band edges and each of these band edges can have a transitionregion from the pass-band to a stop band such that the transition regionranges from 5 MHz to 250 MHz.

In a specific example, the insulating materials include a siliconnitride bearing material, an oxide bearing material, or combinationsthereof.

In a specific example, the present device can be configured as a bulkacoustic wave (BAW) filter device. Each of the first, second, third, andfourth resonators can be a BAW resonator. Similarly, each of the first,second, third, and fourth shunt resonators can be BAW resonators. Thepresent device can further include one or more additional resonatordevices numbered from N to M, where N is four and M is twenty.Similarly, the present device can further include one or more additionalshunt resonator devices numbered from N to M, where N is four and M istwenty. In other examples, the present device can include a plurality ofresonator devices configured with a plurality of shunt resonator devicesin a ladder configuration, a lattice configuration, or otherconfiguration as previously described.

In an example, the present invention provides an RF filter circuitdevice using a lattice configuration including a plurality of topresonator devices, a plurality of bottom resonator devices, and aplurality of shunt configuration resonator devices. Similar to theladder configuration RF filter circuit, each of the plurality of top andbottom resonator devices includes at least a capacitor device, a bottomelectrode, a piezoelectric material, a top electrode, and an insulatingmaterial configured in accordance to any of the resonator examplesdescribed previously. The plurality of top resonator devices isconfigured in a top serial configuration and the plurality of bottomresonator devices is configured in a bottom serial configuration.Further, the plurality of shunt configuration resonators is configuredin a cross-coupled configuration such that a pair of the plurality ofshunt configuration resonators is cross-coupled between the top serialconfiguration and the bottom serial configuration and between one of theplurality of top resonator devices and one of the plurality of thebottom resonator devices. In a specific example, this device alsoincludes a plurality of inductor devices, wherein the plurality ofinductor devices are configured such that one of the plurality ofinductor devices is coupled between the differential input port, one ofthe plurality of inductor devices is coupled between the differentialoutput port, and one of the plurality of inductor devices is coupled tothe top serial configuration and the bottom serial configuration betweeneach cross-coupled pair of the plurality of shunt configurationresonators.

In an example, the RF circuit device in a lattice configuration can alsobe described as follows. The device can include a differential inputport, a top serial configuration, a bottom serial configuration, a firstlattice configuration, a second lattice configuration, and adifferential output port. The top serial configuration can include afirst top node, a second top node, and a third top node. A first topresonator can be coupled between the first top node and the second topnode, while a second top resonator can be coupled between the second topnode and the third top node. Similarly, the bottom serial configurationcan include a first bottom node, a second bottom node, and a thirdbottom node. A first bottom resonator can be coupled between the firstbottom node and the second bottom node, while a second bottom resonatorcan be coupled between the second bottom node and the third bottom node.

In an example, the first lattice configuration includes a first shuntresonator cross-coupled with a second shunt resonator and coupledbetween the first top resonator of the top serial configuration and thefirst bottom resonator of the bottom serial configuration. Similarly,the second lattice configuration can include a first shunt resonatorcross-coupled with a second shunt resonator and coupled between thesecond top resonator of the top serial configuration and the secondbottom resonator of the bottom serial configuration. The top serialconfiguration and the bottom serial configuration can each be coupled toboth the differential input port and the differential output port.

In a specific example, the device further includes a first balun coupledto the differential input port and a second balun coupled to thedifferential output port. The device can further include an inductordevice coupled between the differential input and output ports. In aspecific example, the device can further include a first inductor devicecoupled between the first top node of the top serial configuration andthe first bottom node of the bottom serial configuration; a secondinductor device coupled between the second top node of the top serialconfiguration and the second bottom node of the bottom serialconfiguration; and a third inductor device coupled between the third topnode of the top serial configuration and the third bottom node of thebottom serial configuration.

The packaging approach includes but is not limited to wafer levelpackaging (WLP), WLP-plus-cap wafer approach, flip-chip, chip and bondwire, as shown in FIGS. 66A, 66B, 67A and 67B. One or more RF filterchips and one or more filter bands can be packaged within the samehousing configuration. Each RF filter band within the package caninclude one or more resonator filter chips and passive elements(capacitors, inductors) can be used to tailor the bandwidth andfrequency spectrum characteristic. For a 5G-Wi-Fi system application, apackage configuration including 5 RF filter bands, including the n77,n78, n79, and a 5.15-5.835 GHz (U-NII-1, U-NII-2A, UNII-2C and U-NII-3)bandpass solutions is capable using BAW RF filter technology. For aTri-Band Wi-Fi system application, a package configuration including 3RF filter bands, including the 2.4-2.5 GHz, 5.15-5.835 GHz and5.945-7.125 GHz bandpass solutions, is capable using BAW RF filtertechnology. The 2.4-2.5 GHz filter solution can be either surfaceacoustic wave (SAW) or BAW, whereas the 5.15-5.835 GHz and 5.945-7.125GHz bands are likely BAW given the high frequency capability of BAW.

FIG. 66A is a simplified diagram illustrating a packing approachaccording to an example of the present invention. As shown, device 6601is packaged using a conventional die bond of an RF filter die 6610 tothe base 6620 of a package and metal bond wires 6630 to the RF filterchip from the circuit interface 6640.

FIG. 66B is as simplified diagram illustrating a packing approachaccording to an example of the present invention. As shown, device 6602is packaged using a flip-mount wafer level package (WLP) showing the RFfilter silicon die 6610 mounted to the circuit interface 6640 usingcopper pillars 6631 or other high-conductivity interconnects.

FIGS. 67A-67B are simplified diagrams illustrating packing approachesaccording to examples of the present invention. In FIG. 67A, device 6701shows an alternate version of a WLP utilizing a BAW RF filter circuitMEMS device 6731 and a substrate 6711 to a cap wafer 6741. In anexample, the cap wafer 6741 may include thru-silicon-vias (TSVs) toelectrically connect the RF filter MEMS device 6731 to the topside ofthe cap wafer (not shown in the figure). The cap wafer 6741 can becoupled to a dielectric layer 6721 overlying the substrate 6711 andsealed by sealing material 6751.

In FIG. 67B, device 6702 shows another version of a WLP bonding aprocessed BAW substrate 6712 to a cap layer 6742. As discussedpreviously, the cap wafer 6742 may include thru-silicon vias (TSVs) 6732spatially configured through a dielectric layer 6722 to electricallyconnect the BAW resonator within the BAW substrate 6712 to the topsideof the cap wafer. Similar to the device of FIG. 67A, the cap wafer 6742can be coupled to a dielectric layer overlying the BAW substrate 6712and sealed by sealing material 6752. Of course, there can be othervariations, modifications, and alternatives.

In an example, the present diplexer passes frequencies in the two rangesand rejects frequencies outside of these two passbands. Additionalfeatures of the 5.1-7.1 GHz acoustic wave diplexer circuit are providedbelow. The circuit symbol which is used to reference the RF diplexerbuilding block is provided in FIG. 68. The electrical performancespecifications of the diplexer are provided in FIG. 69 and the passbandperformance of the diplexer is provided in FIGS. 70A and 70B.

In various examples, the present diplexer can have certain features. Themultiple RF resonator filter circuit chip die configurations can be lessthan 2 mm×2 mm×0.5 mm; in a specific example, the die configuration istypically less than 1 mm×1 mm×0.2 mm. The packaged device has anultra-small form factor, such as a 1.1 mm×0.9 mm×0.3 mm for a WLPapproach, shown in FIGS. 66B, 67A, and 67B. A larger form factor, suchas a 2 mm×2.5 mm×0.9 mm, is available using a wire bond approach, shownin FIG. 66A, for higher power applications. In a specific example, thedevice is configured with a single-ended 50-Ohm antenna, andtransmitter/receiver (Tx/Rx) ports. The high rejection of the deviceenables coexistence with adjacent Wi-Fi U-NII-1 to U-NII-3 and U-NII-5to U-NII-8 bands. The device can also be characterized by a high powerrating (maximum greater than +30 dBm), a low insertion loss pass-bandfilter with less than 3.0 dB transmission loss, and performance over atemperature range from −40 degrees Celsius to +85 degrees Celsius.Further, in a specific example, the device is RoHS (Restriction ofHazardous Substances) compliant and uses Pb-free (lead-free) packaging.

FIG. 68 is a simplified circuit diagram illustrating a 3-port BAW RFdiplexer circuit according to an example of the present invention. Asshown, circuit 6800 includes a first port (“Port 1”) 6811 coupled to afirst filter 6821 and a second port (“Port 2”) 6812 coupled to a secondfilter 6822. A third port (“Port 3”) is also coupled to both the firstfilter 6821 and the second filter 6821. In an example, the first port6811 represents a connection from a transmitter (TX) or receiver (RX) tothe first filter 6821, the second port represents a connection from a TXor RX to the second filter 6822 and the third port represents aconnection from the diplexer, including the first and second filters6821, 6822, to an antenna (ANT). The TX, RX, and ANT components of thediplexer can be configured for the particular frequency passbands offirst and second filters. Examples of the first and second filters aredescribed with reference to FIGS. 69A and 69B, which show differentpassband frequency gaps between the first and second filters.

FIG. 69A is a simplified table of diplexer parameters according to anexample of the present invention. As shown, table 6901 includeselectrical specifications for a 5.1-7.1 GHz RF resonator diplexercircuit including parameters for a first filter and a second filter. Thecircuit parameters are provided along with the specification units,minimum, typical and maximum specification values.

In this case, the first filter is characterized by a passband rangingfrom 5150 MHz to 5895 MHz (5522.5 MHz center frequency). Insertion lossin the passband is typically around 2 dB, with a maximum of 3 dB. Ripplein the passband is typically around 1 dB, with a maximum of 2.0 dB.Return loss in the passband is typically around 12 dB, with a minimum of10 dB. Also, the first filter can have a minimum attenuation of 25 dB(typically around 35 dB) for a frequency range of 700 MHz to 2400 MHz; aminimum attenuation of 30 dB (typically around 40 dB) for a frequencyrange of 2400 MHz to 2500 MHz; a minimum attenuation of 25 dB (typicallyaround 35 dB) for a frequency range of 3300 MHz to 5000 MHz; a minimumattenuation of 35 dB (typically around 40 dB) for a frequency range of5935 MHz to 6015 MHz; a minimum attenuation of 45 dB (typically around50 dB) for a frequency range of 6015 MHz to 7125 MHz; and a minimumattenuation of 25 dB (typically around 35 dB) for a frequency range of7200 MHz to 12000 MHz.

The second filter is characterized by a passband ranging from 5945 MHzto 7125 MHz (6535 MHz center frequency). Insertion loss in the passbandis typically around 2 dB, with a maximum of 3 dB. Ripple in the passbandis typically around 1 dB, with a maximum of 2.0 dB. Return loss in thepassband is typically around 12 dB, with a minimum of 10 dB. Also, thesecond filter can have a minimum attenuation of 25 dB (typically around35 dB) for a frequency range of 700 MHz to 2400 MHz; a minimumattenuation of 30 dB (typically around 40 dB) for a frequency range of2400 MHz to 2500 MHz; a minimum attenuation of 25 dB (typically around35 dB) for a frequency range of 3300 MHz to 5000 MHz; a minimumattenuation of 45 dB (typically around 50 dB) for a frequency range of5150 MHz to 5815 MHz; a minimum attenuation of 35 dB (typically around40 dB) for a frequency range of 5815 MHz to 5895 MHz; and a minimumattenuation of 45 dB (typically around 50 dB) for a frequency range of6000 MHz to 12000 MHz.

The diplexer can have a minimum third order intercept of 49 dB, and amaximum RF input power of 1 W. The I/O resistance is 50 ohms nominal forall three ports. The device operating temperature ranges from −40degrees Celsius to 85 degrees Celsius. Further, the diplexer packagesize can be 2.7 mm×2.7 mm×0.8 mm.

FIG. 69B is a simplified table of diplexer parameters according to anexample of the present invention. As shown, table 6902 includeselectrical specifications for a 5.1-7.1 GHz RF resonator diplexercircuit including parameters for a first filter and a second filter. Thecircuit parameters are provided along with the specification units,minimum, typical and maximum specification values.

In this case, the first filter is characterized by a passband rangingfrom 5150 MHz to 5895 MHz (5522.5 MHz center frequency). Insertion lossin the passband is typically around 2 dB, with a maximum of 2.5 dB.Ripple in the passband is typically around 0.8 dB, with a maximum of 1.2dB. Return loss in the passband is typically around 15 dB, with aminimum of 12 dB. Also, the first filter can have a minimum attenuationof 40 dB (typically around 45 dB) for a frequency range of 30 MHz to1000 MHz; a minimum attenuation of 35 dB (typically around 40 dB) for afrequency range of 1000 MHz to 2700 MHz; a minimum attenuation of 30 dB(typically around 35 dB) for a frequency range of 3300 MHz to 4200 MHz;a minimum attenuation of 30 dB (typically around 35 dB) for a frequencyrange of 4400 MHz to 5000 MHz; a minimum attenuation of 50 dB (typicallyaround 55 dB) for a frequency range of 6105 MHz to 7125 MHz; a minimumattenuation of 25 dB (typically around 30 or 35 dB) for a frequencyrange of 7300 MHz to 8000 MHz; and a minimum attenuation of 30 dB(typically around 35 dB) for a frequency range of 10000 MHz to 11750MHz.

The second filter is characterized by a passband ranging from 6105 MHzto 7125 MHz (6615 MHz center frequency). Insertion loss in the passbandis typically around 2 dB, with a maximum of 2.5 dB. Ripple in thepassband is typically around 0.8 dB, with a maximum of 1.2 dB. Returnloss in the passband is typically around 15 dB, with a minimum of 12 dB.Also, the second filter can have a minimum attenuation of 40 dB(typically around 45 dB) for a frequency range of 30 MHz to 1000 MHz; aminimum attenuation of 35 dB (typically around 40 dB) for a frequencyrange of 1000 MHz to 2700 MHz; a minimum attenuation of 30 dB (typicallyaround 35 dB) for a frequency range of 3300 MHz to 4200 MHz; a minimumattenuation of 30 dB (typically around 35 dB) for a frequency range of4400 MHz to 5000 MHz; a minimum attenuation of 50 dB (typically around55 dB) for a frequency range of 5170 MHz to 5895 MHz; a minimumattenuation of 25 dB (typically around 30 or 35 dB) for a frequencyrange of 7300 MHz to 8000 MHz; and a minimum attenuation of 30 dB(typically around 35 dB) for a frequency range of 11500 MHz to 14300MHz.

The diplexer can have a typical input power of 28 dBm, with a maximum of30 dBm. The I/O resistance is 50 ohms nominal for all three ports. Thedevice operating temperature ranges from −40 degrees Celsius to 85degrees Celsius. Further, the diplexer package size can be 2.5 mm×2.5mm×0.8 mm.

FIG. 70A is a simplified graph representing insertion loss overfrequency according to an example of the present invention. As shown,graph 7001 represents passband modeled responses 7011, 7012 for a5.1-7.1 GHz RF diplexer (i.e., diplexer described in FIG. 69A) using aladder RF filter configuration (curve 7011 represents the 5.15-5.835 GHzfilter of the diplexer and curve 7012 represents the 5.945-7.125 GHzfilter of the diplexer). The modeled curves 7011 and 7012 are thetransmission losses (s21) predicted from a linear simulation toolincorporating non-linear, full 3-dimensional (3D) electromagnetic (EM)simulation.

FIG. 70B is a simplified graph representing insertion loss overfrequency according to an example of the present invention. As shown,graph 7002 represents passband modeled responses 7021, 7022 for a5.1-7.1 GHz RF diplexer (i.e., diplexer described in FIG. 69B) using aladder RF filter configuration (curve 7021 represents the 5.15-5.895 GHzfilter of the diplexer and curve 7022 represents the 6.105-7.125 GHzfilter of the diplexer). The modeled curves 7021 and 7022 are thetransmission losses (s21) predicted from a linear simulation toolincorporating non-linear, full 3-dimensional (3D) electromagnetic (EM)simulation.

FIG. 71A is a simplified graph representing insertion loss overfrequency according to an example of the present invention. As shown,graph 7101 represents wideband modeled responses 7112, 7111 for a5.1-7.1 GHz RF diplexer (i.e., diplexer described in FIG. 69A) using aladder RF filter configuration (curve 7111 represents the 5.15-5.835 GHzfilter of the diplexer and curve 7112 represents the 5.945-7.125 GHzfilter of the diplexer). The modeled curves 7111 and 7112 are thetransmission losses (s21) predicted from a linear simulation toolincorporating non-linear, full 3-dimensional (3D) electromagnetic (EM)simulation.

FIG. 71B is a simplified graph representing insertion loss overfrequency according to an example of the present invention. As shown,graph 7102 represents wideband modeled responses 7121, 7122 for a5.1-7.1 GHz RF diplexer (i.e., diplexer described in FIG. 69B) using aladder RF filter configuration (curve 7121 represents the 5.15-5.895 GHzfilter of the diplexer and curve 7122 represents the 6.105-7.125 GHzfilter of the diplexer). The modeled curves 7121 and 7122 are thetransmission losses (s21) predicted from a linear simulation toolincorporating non-linear, full 3-dimensional (3D) electromagnetic (EM)simulation.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. As an example, the packaged device can include any combination ofelements described above, as well as outside of the presentspecification. Therefore, the above description and illustrations shouldnot be taken as limiting the scope of the present invention which isdefined by the appended claims.

What is claimed is:
 1. An RF diplexer device, the device comprising: afirst filter circuit configured to receive a first input signal and toproduce a first filtered signal; a second filter circuit configured toreceive a second input signal and to produce a second filtered signal;wherein each of the first and second filter circuits comprises aplurality of series resonators and a plurality of shunt resonators;wherein each of the series resonators comprises a substrate memberhaving a cavity region and an upper surface region contiguous with anopening of the cavity region, a bottom electrode within a portion of thecavity region, a piezoelectric material overlying the upper surfaceregion and the bottom electrode, a top electrode overlying thepiezoelectric material and overlying the bottom electrode, and aninsulating material overlying the top electrode; wherein the firstfilter circuit has a first circuit response configured from the serialconfiguration of the first filter circuit and the parallel configurationof the first filter circuit to achieve a first transmission loss from afirst pass band having a first characteristic frequency centered around5.4925 GHz and having a bandwidth from 5.150 GHz to 5.835 GHz; andwherein the second filter circuit has a second circuit responseconfigured from the serial configuration of the second filter circuitand the parallel configuration of the second filter circuit to achieve asecond transmission loss from a second pass band having a secondcharacteristic frequency centered around 6.535 GHz and having abandwidth from 5.945 GHz to 7.125 GHz; and a multiplexer coupled to thefirst filter circuit and the second filter circuit and configured toselect between the first filtered signal and the second filtered signal.2. The device of claim 1 wherein the piezoelectric material comprises asingle crystal aluminum nitride (AlN) bearing material, a single crystalaluminum scandium nitride (AlScN) bearing material, a single crystalgallium nitride (GaN) bearing material, a single crystal galliumaluminum nitride (GaAlN) bearing material, or a single crystal magnesiumhafnium aluminum nitride (MgHfAlN) material.
 3. The device of claim 1wherein the piezoelectric material comprises a polycrystalline aluminumnitride (AlN) bearing material, a polycrystalline aluminum scandiumnitride (AlScN) bearing material, a polycrystalline gallium nitride(GaN) bearing material, a polycrystalline gallium aluminum nitride(GaAlN) bearing material, or a polycrystalline magnesium hafniumaluminum nitride (MgHfAlN) material.
 4. The device of claim 1 whereinthe insulating material comprises a silicon nitride bearing material oran oxide bearing material.
 5. The device of claim 1 wherein each of thefirst pass band and the second pass band is characterized by a band edgeon each side of the pass band having an amplitude difference rangingfrom 10 dB to 60 dB; and wherein each of the first pass band and thesecond pass band has a pair of band edges, each of the band edges havinga transition region from the pass-band to a stop band such that thetransition region ranges from 5 MHz to 250 MHz.
 6. The device of claim 1wherein the first filter circuit comprises a maximum insertion loss of3.0 dB within the first pass band, a maximum amplitude variationcharacterizing the pass-band of less than 2.0 dB, and a minimum returnloss characterizing the pass-band of 10 dB; and wherein the secondfilter circuit comprises a maximum insertion loss of 3.0 dB within thesecond pass band, a maximum amplitude variation characterizing thepass-band of 2.0 dB, and a minimum return loss characterizing thepass-band of 10 dB; and further comprising an operating temperatureranging from −40 Degrees Celsius to 85 Degrees Celsius, a microwavecharacteristic impedance of 50 Ohms, a maximum power handling capabilitywithin the pass-band of +30 dBm or 1 Watt.
 7. The device of claim 1wherein the first filter circuit comprises a minimum attenuation of 25dB for a frequency range of 700 MHz to 2400 MHz, a minimum attenuationof 30 dB for a frequency range of 2400 MHz to 2500 MHz, a minimumattenuation of 25 dB for a frequency range of 3300 MHz to 5000 MHz, aminimum attenuation of 35 dB for a frequency range of 5935 MHz to 6015MHz, a minimum attenuation of 45 dB for a frequency range of 6015 MHz to7125 MHz, a minimum attenuation of 25 dB for a frequency range 7200 MHzto 12000 MHz; and wherein the second filter circuit comprises a minimumattenuation of 25 dB for a frequency range of 9 MHz to 2400 MHz, aminimum attenuation of 30 dB for a frequency range of 2400 MHz to 2500MHz, a minimum attenuation of 25 dB for a frequency range of 3300 MHz to5000 MHz, a minimum attenuation of 45 dB for a frequency range of 5150MHz to 5815 MHz, a minimum attenuation of 35 dB for a frequency range of5815 MHz to 5895 MHz, a minimum attenuation of 45 dB for a frequencyrange 6000 MHz to 12000 MH.
 8. The device of claim 1 wherein, for eachof the first and second filter circuits, the plurality of seriesresonators is configured in a serial configuration and the plurality ofshunt resonators is configured in a parallel configuration, the serialconfiguration and the parallel configuration being configured as aladder configuration; wherein the serial configuration of the firstfilter circuit forms a resonance profile and an anti-resonance profile;and the parallel configuration of the first filter circuit forms aresonance profile and an anti-resonance profile such that the resonanceprofile from the serial configuration of the first filter circuit isoff-set with the anti-resonance profile of the parallel configuration ofthe first filter circuit to form the first pass band; and wherein theserial configuration of the second filter circuit forms a resonanceprofile and an anti-resonance profile; and the parallel configuration ofthe second filter circuit forms a resonance profile and ananti-resonance profile such that the resonance profile from the serialconfiguration of the second filter circuit is off-set with theanti-resonance profile of the parallel configuration of the secondfilter circuit to form the second pass band.
 9. The device of claim 1wherein, for each of the first and second filter circuits, the pluralityof series resonators comprises a first plurality of series resonatorsand a second plurality of series resonators, the first plurality ofseries resonators being configured in a first serial configuration andthe second plurality of series resonators being configured in a secondserial configuration; and wherein, for each of the first and secondfilter circuits, the plurality of shunt resonators comprises a pluralityof shunt resonator pairs in a lattice configuration, each of theplurality of shunt resonator pairs being cross-coupled between one ofthe first plurality of series resonators and one of the second pluralityof series resonators.
 10. The device of claim 9 wherein each of thefirst and second filter circuits comprises a plurality of baluns; andwherein, for each of the first and second filter circuits, each of theplurality of baluns is coupled between the first serial configurationand the second serial configuration, and each of the plurality of balunsis configured between each of the plurality of shunt resonator pairs.11. An RF diplexer device, the device comprising: a first inputinductor; a first filter circuit coupled to the first input inductor,the first filter circuit configured to receive a first input signal overthe first input inductor and to produce a first filtered signal; asecond input inductor; a second filter circuit coupled to the secondinput inductor, the second filter circuit configured to receive a secondinput signal over the second input inductor and to produce a secondfiltered signal; wherein each of the first and second filter circuitscomprises a plurality of series resonators and a plurality of shuntresonators; wherein each of the resonators comprises a substrate memberhaving a cavity region and an upper surface region contiguous with anopening of the cavity region, a bottom electrode within a portion of thecavity region, a piezoelectric material overlying the upper surfaceregion and the bottom electrode, a top electrode overlying thepiezoelectric material and overlying the bottom electrode, and aninsulating material overlying the top electrode; wherein the firstfilter circuit has a first circuit response configured from the serialconfiguration of the first filter circuit and the parallel configurationof the first filter circuit to achieve a first transmission loss from afirst pass band having a first characteristic frequency centered around5.4925 GHz and having a bandwidth from 5.150 GHz to 5.835 GHz; andwherein the second filter circuit has a second circuit responseconfigured from the serial configuration of the second filter circuitand the parallel configuration of the second filter circuit to achieve asecond transmission loss from a second pass band having a secondcharacteristic frequency centered around 6.535 GHz and having abandwidth from 5.945 GHz to 7.125 GHz a first output inductor coupled tothe first filter circuit; a second output inductor coupled to the secondfilter circuit; and a third output inductor coupled to the first andsecond output inductors; wherein the third output inductor is configuredto receive the first filtered signal over the first output inductor andto receive the second filtered signal over the second output inductor.12. The device of claim 11 wherein, for each of the first and secondfilter circuits, the plurality of series resonators is configured in aserial configuration and the plurality of shunt resonators is configuredin a parallel configuration, the serial configuration and the parallelconfiguration being configured as a ladder configuration.
 13. The deviceof claim 11 wherein, for each of the first and second filter circuits,the plurality of series resonators comprises a first plurality of seriesresonators and a second plurality of series resonators, the firstplurality of series resonators being configured in a first serialconfiguration and the second plurality of series resonators beingconfigured in a second serial configuration; and wherein, for each ofthe first and second filter circuits, the plurality of shunt resonatorscomprises a plurality of shunt resonator pairs in a latticeconfiguration, each of the plurality of shunt resonator pairs beingcross-coupled between one of the first plurality of series resonatorsand one of the second plurality of series resonators.
 14. The device ofclaim 13 wherein each of the first and second filter circuits comprisesa plurality of baluns; and wherein, for each of the first and secondfilter circuits, each of the plurality of baluns is coupled between thefirst serial configuration and the second serial configuration, and eachof the plurality of baluns is configured between each of the pluralityof shunt resonator pairs.
 15. The device of claim 11 wherein thepiezoelectric material comprises a single crystal aluminum nitride (AlN)bearing material, a single crystal aluminum scandium nitride (AlScN)bearing material, a single crystal gallium nitride (GaN) bearingmaterial, a single crystal gallium aluminum nitride (GaAlN) bearingmaterial, or a single crystal magnesium hafnium aluminum nitride(MgHfAlN) material.
 16. The device of claim 11 wherein the piezoelectricmaterial comprises a polycrystalline aluminum nitride (AlN) bearingmaterial, a polycrystalline aluminum scandium nitride (AlScN) bearingmaterial, a polycrystalline gallium nitride (GaN) bearing material, apolycrystalline gallium aluminum nitride (GaAlN) bearing material, or apolycrystalline magnesium hafnium aluminum nitride (MgHfAlN) material.17. The device of claim 11 wherein the insulating material comprises asilicon nitride bearing material or an oxide bearing material.
 18. An RFdiplexer device, the device comprising: a first filter circuitconfigured to receive a first input signal and to produce a firstfiltered signal; a second filter circuit configured to receive a secondinput signal and to produce a second filtered signal; wherein each ofthe first and second filter circuits comprises a plurality of seriesresonators and a plurality of shunt resonators; wherein each of theseries resonators comprises a substrate member having a cavity regionand an upper surface region contiguous with an opening of the cavityregion, a bottom electrode within a portion of the cavity region, apiezoelectric material overlying the upper surface region and the bottomelectrode, a top electrode overlying the piezoelectric material andoverlying the bottom electrode, and an insulating material overlying thetop electrode; wherein the first filter circuit has a first circuitresponse configured from the serial configuration of the first filtercircuit and the parallel configuration of the first filter circuit toachieve a first transmission loss from a first pass band having a firstcharacteristic frequency centered around 5.5225 GHz and having abandwidth from 5.150 GHz to 5.895 GHz; and wherein the second filtercircuit has a second circuit response configured from the serialconfiguration of the second filter circuit and the parallelconfiguration of the second filter circuit to achieve a secondtransmission loss from a second pass band having a second characteristicfrequency centered around 6.615 GHz and having a bandwidth from 6.105GHz to 7.125 GHz; and a multiplexer coupled to the first filter circuitand the second filter circuit and configured to select between the firstfiltered signal and the second filtered signal.
 19. The device of claim18 wherein the piezoelectric material comprises a single crystalaluminum nitride (AlN) bearing material, a single crystal aluminumscandium nitride (AlScN) bearing material, a single crystal galliumnitride (GaN) bearing material, a single crystal gallium aluminumnitride (GaAlN) bearing material, or a single crystal magnesium hafniumaluminum nitride (MgHfAlN) material.
 20. The device of claim 18 whereinthe piezoelectric material comprises a polycrystalline aluminum nitride(AlN) bearing material, a polycrystalline aluminum scandium nitride(AlScN) bearing material, a polycrystalline gallium nitride (GaN)bearing material, a polycrystalline gallium aluminum nitride (GaAlN)bearing material, or a polycrystalline magnesium hafnium aluminumnitride (MgHfAlN) material.
 21. The device of claim 18 wherein theinsulating material comprises a silicon nitride bearing material or anoxide bearing material.
 22. The device of claim 18 wherein each of thefirst pass band and the second pass band is characterized by a band edgeon each side of the pass band having an amplitude difference rangingfrom 10 dB to 60 dB; and wherein each of the first pass band and thesecond pass band has a pair of band edges, each of the band edges havinga transition region from the pass-band to a stop band such that thetransition region ranges from 5 MHz to 250 MHz.
 23. The device of claim18 wherein the first filter circuit comprises a maximum insertion lossof 2.5 dB within the first pass band, a maximum amplitude variationcharacterizing the pass-band of 1.2 dB, and a minimum return losscharacterizing the pass-band of 12 dB; and wherein the second filtercircuit comprises a maximum insertion loss of 2.5 dB within the secondpass band, a maximum amplitude variation characterizing the pass-band of1.2 dB, and a minimum return loss characterizing the pass-band of 12 dB;and further comprising an operating temperature ranging from −40 DegreesCelsius to 85 Degrees Celsius, a microwave characteristic impedance of50 Ohms, a maximum power handling capability within the pass-band of +30dBm or 1 Watt.
 24. The device of claim 18 wherein the first filtercircuit comprises a minimum attenuation of 40 dB for a frequency rangeof 30 MHz to 1000 MHz, a minimum attenuation of 35 dB for a frequencyrange of 1000 MHz to 2700 MHz, a minimum attenuation of 30 dB for afrequency range of 3300 MHz to 4200 MHz, a minimum attenuation of 30 dBfor a frequency range of 4400 MHz to 5000 MHz, a minimum attenuation of50 dB for a frequency range of 6105 MHz to 7125 MHz, a minimumattenuation of 25 dB for a frequency range of 7300 MHz to 8000 MHz, anda minimum attenuation of 30 dB for a frequency range 10000 MHz to 11750MHz; and wherein the second filter circuit comprises a minimumattenuation of 40 dB for a frequency range of 30 MHz to 1000 MHz, aminimum attenuation of 35 dB for a frequency range of 1000 MHz to 2700MHz, a minimum attenuation of 30 dB for a frequency range of 3300 MHz to4200 MHz, a minimum attenuation of 30 dB for a frequency range of 4400MHz to 5000 MHz, a minimum attenuation of 50 dB for a frequency range of5170 MHz to 5895 MHz, a minimum attenuation of 25 dB for a frequencyrange of 7300 MHz to 8000 MHz, and a minimum attenuation of 30 dB for afrequency range 11500 MHz to 12000 MHz.
 25. The device of claim 18wherein, for each of the first and second filter circuits, the pluralityof series resonators is configured in a serial configuration and theplurality of shunt resonators is configured in a parallel configuration,the serial configuration and the parallel configuration being configuredas a ladder configuration; wherein the serial configuration of the firstfilter circuit forms a resonance profile and an anti-resonance profile;and the parallel configuration of the first filter circuit forms aresonance profile and an anti-resonance profile such that the resonanceprofile from the serial configuration of the first filter circuit isoff-set with the anti-resonance profile of the parallel configuration ofthe first filter circuit to form the first pass band; and wherein theserial configuration of the second filter circuit forms a resonanceprofile and an anti-resonance profile; and the parallel configuration ofthe second filter circuit forms a resonance profile and ananti-resonance profile such that the resonance profile from the serialconfiguration of the second filter circuit is off-set with theanti-resonance profile of the parallel configuration of the secondfilter circuit to form the second pass band.
 26. The device of claim 18wherein, for each of the first and second filter circuits, the pluralityof series resonators comprises a first plurality of series resonatorsand a second plurality of series resonators, the first plurality ofseries resonators being configured in a first serial configuration andthe second plurality of series resonators being configured in a secondserial configuration; and wherein, for each of the first and secondfilter circuits, the plurality of shunt resonators comprises a pluralityof shunt resonator pairs in a lattice configuration, each of theplurality of shunt resonator pairs being cross-coupled between one ofthe first plurality of series resonators and one of the second pluralityof series resonators.
 27. The device of claim 26 wherein each of thefirst and second filter circuits comprises a plurality of baluns; andwherein, for each of the first and second filter circuits, each of theplurality of baluns is coupled between the first serial configurationand the second serial configuration, and each of the plurality of balunsis configured between each of the plurality of shunt resonator pairs.28. An RF diplexer device, the device comprising: a first inputinductor; a first filter circuit coupled to the first input inductor,the first filter circuit configured to receive a first input signal overthe first input inductor and to produce a first filtered signal; asecond input inductor; a second filter circuit coupled to the secondinput inductor, the second filter circuit configured to receive a secondinput signal over the second input inductor and to produce a secondfiltered signal; wherein each of the first and second filter circuitscomprises a plurality of series resonators and a plurality of shuntresonators; wherein each of the resonators comprises a substrate memberhaving a cavity region and an upper surface region contiguous with anopening of the cavity region, a bottom electrode within a portion of thecavity region, a piezoelectric material overlying the upper surfaceregion and the bottom electrode, a top electrode overlying thepiezoelectric material and overlying the bottom electrode, and aninsulating material overlying the top electrode; wherein the firstfilter circuit has a first circuit response configured from the serialconfiguration of the first filter circuit and the parallel configurationof the first filter circuit to achieve a first transmission loss from afirst pass band having a first characteristic frequency centered around5.5225 GHz and having a bandwidth from 5.150 GHz to 5.895 GHz; andwherein the second filter circuit has a second circuit responseconfigured from the serial configuration of the second filter circuitand the parallel configuration of the second filter circuit to achieve asecond transmission loss from a second pass band having a secondcharacteristic frequency centered around 6.615 GHz and having abandwidth from 6.105 GHz to 7.125 GHz; a first output inductor coupledto the first filter circuit; a second output inductor coupled to thesecond filter circuit; and a third output inductor coupled to the firstand second output inductors; wherein the third output inductor isconfigured to receive the first filtered signal over the first outputinductor and to receive the second filtered signal over the secondoutput inductor.
 29. The device of claim 28 wherein, for each of thefirst and second filter circuits, the plurality of series resonators isconfigured in a serial configuration and the plurality of shuntresonators is configured in a parallel configuration, the serialconfiguration and the parallel configuration being configured as aladder configuration.
 30. The device of claim 28 wherein, for each ofthe first and second filter circuits, the plurality of series resonatorscomprises a first plurality of series resonators and a second pluralityof series resonators, the first plurality of series resonators beingconfigured in a first serial configuration and the second plurality ofseries resonators being configured in a second serial configuration; andwherein, for each of the first and second filter circuits, the pluralityof shunt resonators comprises a plurality of shunt resonator pairs in alattice configuration, each of the plurality of shunt resonator pairsbeing cross-coupled between one of the first plurality of seriesresonators and one of the second plurality of series resonators.
 31. Thedevice of claim 30 wherein each of the first and second filter circuitscomprises a plurality of baluns; and wherein, for each of the first andsecond filter circuits, each of the plurality of baluns is coupledbetween the first serial configuration and the second serialconfiguration, and each of the plurality of baluns is configured betweeneach of the plurality of shunt resonator pairs.
 32. The device of claim28 wherein the piezoelectric material comprises a single crystalaluminum nitride (AlN) bearing material, a single crystal aluminumscandium nitride (AlScN) bearing material, a single crystal galliumnitride (GaN) bearing material, a single crystal gallium aluminumnitride (GaAlN) bearing material, or a single crystal magnesium hafniumaluminum nitride (MgHfAlN) material.
 33. The device of claim 28 whereinthe piezoelectric material comprises a polycrystalline aluminum nitride(AlN) bearing material, a polycrystalline aluminum scandium nitride(AlScN) bearing material, a polycrystalline gallium nitride (GaN)bearing material, a polycrystalline gallium aluminum nitride (GaAlN)bearing material, or a polycrystalline magnesium hafnium aluminumnitride (MgHfAlN) material.
 34. The device of claim 28 wherein theinsulating material comprises a silicon nitride bearing material or anoxide bearing material.